index : litmus-rt.git	archive/unc-master-3.0 archived-2013.1 archived-private-master archived-semi-part demo ecrts-pgm-final ecrts14-pgm-final gpusync-rtss12 gpusync/staging linux-tip litmus2008-patch-series master pgm prop/litmus-signals prop/robust-tie-break staging test tracing-devel v2.6.34-with-arm-patches v2015.1 wip-2011.2-bbb wip-2011.2-bbb-trace wip-2012.3-gpu wip-2012.3-gpu-preport wip-2012.3-gpu-rtss13 wip-2012.3-gpu-sobliv-budget-w-kshark wip-aedzl-final wip-aedzl-revised wip-arbit-deadline wip-aux-tasks wip-bbb wip-bbb-prio-don wip-better-break wip-binary-heap wip-budget wip-color wip-color-jlh wip-d10-hz1000 wip-default-clustering wip-dissipation-jerickso wip-dissipation2-jerickso wip-ecrts14-pgm wip-edf-hsb wip-edf-os wip-edf-tie-break wip-edzl-critique wip-edzl-final wip-edzl-revised wip-events wip-extra-debug wip-fix-switch-jerickso wip-fix3 wip-fmlp-dequeue wip-ft-irq-flag wip-gpu-cleanup wip-gpu-interrupts wip-gpu-rtas12 wip-gpu-rtss12 wip-gpu-rtss12-srp wip-gpusync-merge wip-ikglp wip-k-fmlp wip-kernel-coloring wip-kernthreads wip-klmirqd-to-aux wip-kshark wip-litmus-3.2 wip-litmus2011.2 wip-litmus3.0-2011.2 wip-master-2.6.33-rt wip-mc wip-mc-bipasa wip-mc-jerickso wip-mc2-cache-slack wip-mcrit-mac wip-merge-3.0 wip-merge-v3.0 wip-migration-affinity wip-mmap-uncache wip-modechange wip-nested-locking wip-omlp-gedf wip-pai wip-percore-lib wip-performance wip-pgm wip-pgm-split wip-pm-ovd wip-prio-inh wip-prioq-dgl wip-refactored-gedf wip-release-master-fix wip-robust-tie-break wip-rt-kshark wip-rtas12-pgm wip-semi-part wip-semi-part-edfos-jerickso wip-shared-lib wip-shared-lib2 wip-shared-mem wip-splitting-jerickso wip-splitting-omlp-jerickso wip-stage-binheap wip-sun-port wip-timer-trace wip-tracepoints
	The LITMUS^RT kernel.	Bjoern Brandenburg

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Branch	Commit message	Author	Age
archive/unc-master-3.0	P-FP: fix BUG_ON releated to priority inheritance	Bjoern Brandenburg	13 years
archived-2013.1	uncachedev: mmap memory that is not cached by CPUs	Glenn Elliott	12 years
archived-private-master	Merge branch 'wip-2.6.34' into old-private-master	Andrea Bastoni	15 years
archived-semi-part	Merge branch 'wip-semi-part' of ssh://cvs/cvs/proj/litmus/repo/litmus2010 int...	Andrea Bastoni	15 years
demo	Further refinements	Jonathan Herman	14 years
ecrts-pgm-final	Merge branch 'wip-ecrts14-pgm' of ssh://rtsrv.cs.unc.edu/home/litmus/litmus-r...	Glenn Elliott	12 years
ecrts14-pgm-final	Merge branch 'wip-ecrts14-pgm' of ssh://rtsrv.cs.unc.edu/home/litmus/litmus-r...	Glenn Elliott	12 years
gpusync-rtss12	Final GPUSync implementation.	Glenn Elliott	12 years
gpusync/staging	Rename IKGLP R2DGLP.	Glenn Elliott	12 years
linux-tip	Merge branch 'slab/urgent' of git://git.kernel.org/pub/scm/linux/kernel/git/p...	Linus Torvalds	15 years
litmus2008-patch-series	add i386 feather-trace implementation	Bjoern B. Brandenburg	16 years
master	PSN-EDF: use inferred_sporadic_job_release_at	Bjoern Brandenburg	9 years
pgm	make it compile	Glenn Elliott	12 years
prop/litmus-signals	Infrastructure for Litmus signals.	Glenn Elliott	13 years
prop/robust-tie-break	Fixed bug in edf_higher_prio().	Glenn Elliott	13 years
staging	Fix tracepoint compilation error	Felipe Cerqueira	13 years
test	9/23/2016	Namhoon Kim	9 years
tracing-devel	Test kernel tracing events capabilities	Andrea Bastoni	16 years
v2.6.34-with-arm-patches	smsc911x: Add spinlocks around registers access	Catalin Marinas	15 years
v2015.1	Add ARM syscall def for get_current_budget	Bjoern Brandenburg	10 years
wip-2011.2-bbb	Litmus core: simplify np-section protocol	Bjoern B. Brandenburg	14 years
wip-2011.2-bbb-trace	Refactor sched_trace_log_message() -> debug_trace_log_message()	Andrea Bastoni	14 years
wip-2012.3-gpu	SOBLIV draining support for C-EDF.	Glenn Elliott	12 years
wip-2012.3-gpu-preport	pick up last C-RM file	Glenn Elliott	12 years
wip-2012.3-gpu-rtss13	Fix critical bug in GPU tracker.	Glenn Elliott	12 years
wip-2012.3-gpu-sobliv-budget-w-kshark	Proper sobliv draining and many bug fixes.	Glenn Elliott	12 years
wip-aedzl-final	Make it easier to compile AEDZL interfaces in liblitmus.	Glenn Elliott	15 years
wip-aedzl-revised	Add sched_trace data for Apative EDZL	Glenn Elliott	15 years
wip-arbit-deadline	Fix compilation bug.	Glenn Elliott	13 years
wip-aux-tasks	Description of refined aux task inheritance.	Glenn Elliott	13 years
wip-bbb	GSN-EDF & Core: improve debug TRACE'ing for NP sections	Bjoern B. Brandenburg	14 years
wip-bbb-prio-don	use correct timestamp	Bjoern B. Brandenburg	14 years
wip-better-break	Implement hash-based EDF tie-breaking.	Glenn Elliott	13 years
wip-binary-heap	Make C-EDF work with simplified binheap_delete	Glenn Elliott	13 years
wip-budget	Added support for choices in budget policy enforcement.	Glenn Elliott	15 years
wip-color	Summarize schedulability with final record	Jonathan Herman	13 years
wip-color-jlh	sched_color: Fixed two bugs causing crashing on experiment restart and a rare...	Jonathan Herman	13 years
wip-d10-hz1000	Enable HZ=1000 on District 10	Bjoern B. Brandenburg	15 years
wip-default-clustering	Feature: Make default C-EDF clustering compile-time configurable.	Glenn Elliott	15 years
wip-dissipation-jerickso	Update from 2.6.36 to 2.6.36.4	Jeremy Erickson	11 years
wip-dissipation2-jerickso	Update 2.6.36 to 2.6.36.4	Jeremy Erickson	11 years
wip-ecrts14-pgm	Merge branch 'wip-ecrts14-pgm' of ssh://rtsrv.cs.unc.edu/home/litmus/litmus-r...	Glenn Elliott	12 years
wip-edf-hsb	last tested version	Jonathan Herman	14 years
wip-edf-os	Lookup table EDF-os	Jeremy Erickson	12 years
wip-edf-tie-break	Merge branch 'wip-edf-tie-break' of ssh://rtsrv.cs.unc.edu/home/litmus/litmus...	Glenn Elliott	13 years
wip-edzl-critique	Use hr_timer's active checks instead of having own flag.	Glenn Elliott	15 years
wip-edzl-final	Implementation of the EDZL scheduler.	Glenn Elliott	15 years
wip-edzl-revised	Clean up comments.	Glenn Elliott	15 years
wip-events	Added support for tracing arbitrary actions.	Jonathan Herman	15 years
wip-extra-debug	DBG: add additional tracing	Bjoern B. Brandenburg	15 years
wip-fix-switch-jerickso	Attempt to fix race condition with plugin switching	Jeremy Erickson	15 years
wip-fix3	sched: show length of runqueue clock deactivation in /proc/sched_debug	Bjoern B. Brandenburg	15 years
wip-fmlp-dequeue	Improve FMLP queue management.	Glenn Elliott	14 years
wip-ft-irq-flag	Feather-Trace: keep track of interrupt-related interference.	Bjoern B. Brandenburg	14 years
wip-gpu-cleanup	Enable sched_trace log injection from userspace	Glenn Elliott	13 years
wip-gpu-interrupts	Remove option for threading of all softirqs.	Glenn Elliott	14 years
wip-gpu-rtas12	Generalized GPU cost predictors + EWMA. (untested)	Glenn Elliott	13 years
wip-gpu-rtss12	Final GPUSync implementation.	Glenn Elliott	13 years
wip-gpu-rtss12-srp	experimental changes to support GPUs under SRP	Glenn Elliott	13 years
wip-gpusync-merge	Cleanup priority tracking for budget enforcement.	Glenn Elliott	11 years
wip-ikglp	Move RSM and IKGLP imp. to own .c files	Glenn Elliott	13 years
wip-k-fmlp	Merge branch 'mpi-master' into wip-k-fmlp	Glenn Elliott	14 years
wip-kernel-coloring	Added recolor syscall	Namhoon Kim	7 years
wip-kernthreads	Kludge work-queue processing into klitirqd.	Glenn Elliott	15 years
wip-klmirqd-to-aux	Allow klmirqd threads to be given names.	Glenn Elliott	13 years
wip-kshark	Merge branch 'mpi-staging' into wip-kshark	Jonathan Herman	13 years
wip-litmus-3.2	Merge commit 'v3.2' into litmus-staging	Andrea Bastoni	13 years
wip-litmus2011.2	Cleanup: Coding conformance for affinity stuff.	Glenn Elliott	14 years
wip-litmus3.0-2011.2	Feather-Trace: keep track of interrupt-related interference.	Bjoern B. Brandenburg	14 years
wip-master-2.6.33-rt	Avoid deadlock when switching task policy to BACKGROUND (ugly)	Andrea Bastoni	15 years
wip-mc	Removed ARM-specific hacks which disabled less common mixed-criticality featu...	Jonathan Herman	12 years
wip-mc-bipasa	MC-EDF added	bipasa chattopadhyay	13 years
wip-mc-jerickso	Split C/D queues	Jeremy Erickson	15 years
wip-mc2-cache-slack	Manually patched mc^2 related code	Ming Yang	10 years
wip-mcrit-mac	cosmetic	Mac Mollison	15 years
wip-merge-3.0	Prevent Linux to send IPI and queue tasks on remote CPUs.	Andrea Bastoni	14 years
wip-merge-v3.0	Prevent Linux to send IPI and queue tasks on remote CPUs.	Andrea Bastoni	14 years
wip-migration-affinity	NULL affinity dereference in C-EDF.	Glenn Elliott	14 years
wip-mmap-uncache	share branch with others	Glenn Elliott	13 years
wip-modechange	RTSS 2017 submission	Namhoon Kim	8 years
wip-nested-locking	Appears to be working.	Bryan Ward	12 years
wip-omlp-gedf	First implementation of G-OMLP.	Glenn Elliott	15 years
wip-pai	Some cleanup of PAI	Glenn Elliott	14 years
wip-percore-lib	9/21/2016	Namhoon Kim	9 years
wip-performance	CONFIG_DONT_PREEMPT_ON_TIE: Don't preeempt a scheduled task on priority tie.	Glenn Elliott	14 years
wip-pgm	Add PGM support to C-FL	Glenn Elliott	12 years
wip-pgm-split	First draft of C-FL-split	Namhoon Kim	12 years
wip-pm-ovd	Add preemption-and-migration overhead tracing support	Andrea Bastoni	15 years
wip-prio-inh	P-EDF updated to use the generic pi framework.	Glenn Elliott	15 years
wip-prioq-dgl	BUG FIX: Support DGLs with PRIOQ_MUTEX	Glenn Elliott	13 years
wip-refactored-gedf	Generalizd architecture for GEDF-style scheduelrs to reduce code redundancy.	Glenn Elliott	15 years
wip-release-master-fix	bugfix: release master CPU must signal task was picked	Bjoern B. Brandenburg	14 years
wip-robust-tie-break	EDF priority tie-breaks.	Glenn Elliott	13 years
wip-rt-kshark	Move task time accounting into the complete_job method.	Jonathan Herman	13 years
wip-rtas12-pgm	Scheduling of PGM jobs.	Glenn Elliott	13 years
wip-semi-part	Fix compile error with newer GCC	Jeremy Erickson	12 years
wip-semi-part-edfos-jerickso	Use initial CPU set by client	Jeremy Erickson	12 years
wip-shared-lib	TODO: Fix condition checks in replicate_page_move_mapping()	Namhoon Kim	9 years
wip-shared-lib2	RTAS 2017 Submission ver.	Namhoon Kim	9 years
wip-shared-mem	Initial commit for shared library	Namhoon Kim	9 years
wip-splitting-jerickso	Fix release behavior	Jeremy Erickson	13 years
wip-splitting-omlp-jerickso	Bjoern's Dissertation Code with Priority Donation	Jeremy Erickson	13 years
wip-stage-binheap	An efficient binary heap implementation.	Glenn Elliott	13 years
wip-sun-port	Dynamic memory allocation and clean exit for FeatherTrace	Christopher Kenna	15 years
wip-timer-trace	bugfix: C-EDF, clear scheduled field of the correct CPU upon task_exit	Andrea Bastoni	15 years
wip-tracepoints	Add kernel-style events for sched_trace_XXX() functions	Andrea Bastoni	14 years
Tag	Download	Author	Age
2015.1	commit 8e51b37822...	Bjoern Brandenburg	10 years
2013.1	commit bcaacec1ca...	Glenn Elliott	12 years
2012.3	commit c158b5fbe4...	Jonathan Herman	13 years
2012.2	commit b53c479a0f...	Glenn Elliott	13 years
2012.1	commit 83b11ea1c6...	Bjoern B. Brandenburg	14 years
rtas12-mc-beta-exp	commit 8e236ee20f...	Christopher Kenna	14 years
2011.1	commit d11808b5c6...	Christopher Kenna	15 years
v2.6.37-rc4	commit e8a7e48bb2...	Linus Torvalds	15 years
v2.6.37-rc3	commit 3561d43fd2...	Linus Torvalds	15 years
v2.6.37-rc2	commit e53beacd23...	Linus Torvalds	15 years
v2.6.37-rc1	commit c8ddb2713c...	Linus Torvalds	15 years
v2.6.36	commit f6f94e2ab1...	Linus Torvalds	15 years
2010.2	commit 5c5456402d...	Bjoern B. Brandenburg	15 years
v2.6.36-rc8	commit cd07202cc8...	Linus Torvalds	15 years
v2.6.36-rc7	commit cb655d0f3d...	Linus Torvalds	15 years
v2.6.36-rc6	commit 899611ee7d...	Linus Torvalds	15 years
v2.6.36-rc5	commit b30a3f6257...	Linus Torvalds	15 years
v2.6.36-rc4	commit 49553c2ef8...	Linus Torvalds	15 years
v2.6.36-rc3	commit 2bfc96a127...	Linus Torvalds	15 years
v2.6.36-rc2	commit 76be97c1fc...	Linus Torvalds	15 years
v2.6.36-rc1	commit da5cabf80e...	Linus Torvalds	15 years
v2.6.35	commit 9fe6206f40...	Linus Torvalds	15 years
v2.6.35-rc6	commit b37fa16e78...	Linus Torvalds	15 years
v2.6.35-rc5	commit 1c5474a65b...	Linus Torvalds	15 years
v2.6.35-rc4	commit 815c4163b6...	Linus Torvalds	15 years
v2.6.35-rc3	commit 7e27d6e778...	Linus Torvalds	15 years
v2.6.35-rc2	commit e44a21b726...	Linus Torvalds	15 years
v2.6.35-rc1	commit 67a3e12b05...	Linus Torvalds	15 years
2010.1	commit 7c1ff4c544...	Andrea Bastoni	15 years
v2.6.34	commit e40152ee1e...	Linus Torvalds	15 years
v2.6.33.4	commit 4640b4e7d9...	Greg Kroah-Hartman	15 years
v2.6.34-rc7	commit b57f95a382...	Linus Torvalds	15 years
v2.6.34-rc6	commit 66f41d4c5c...	Linus Torvalds	15 years
v2.6.33.3	commit 3e7ad8ed97...	Greg Kroah-Hartman	15 years
v2.6.34-rc5	commit 01bf0b6457...	Linus Torvalds	15 years
v2.6.34-rc4	commit 0d0fb0f9c5...	Linus Torvalds	15 years
v2.6.33.2	commit 19f00f070c...	Greg Kroah-Hartman	15 years
v2.6.34-rc3	commit 2eaa9cfdf3...	Linus Torvalds	15 years
v2.6.34-rc2	commit 220bf991b0...	Linus Torvalds	15 years
v2.6.33.1	commit dbdafe5ccf...	Greg Kroah-Hartman	15 years
v2.6.34-rc1	commit 57d54889cd...	Linus Torvalds	16 years
v2.6.33	commit 60b341b778...	Linus Torvalds	16 years
v2.6.33-rc8	commit 724e6d3fe8...	Linus Torvalds	16 years
v2.6.33-rc7	commit 29275254ca...	Linus Torvalds	16 years
v2.6.33-rc6	commit abe94c756c...	Linus Torvalds	16 years
v2.6.33-rc5	commit 92dcffb916...	Linus Torvalds	16 years
v2.6.33-rc4	commit 7284ce6c9f...	Linus Torvalds	16 years
v2.6.33-rc3	commit 74d2e4f8d7...	Linus Torvalds	16 years
v2.6.33-rc2	commit 6b7b284958...	Linus Torvalds	16 years
v2.6.33-rc1	commit 55639353a0...	Linus Torvalds	16 years
v2.6.32	commit 22763c5cf3...	Linus Torvalds	16 years
v2.6.32-rc8	commit 648f4e3e50...	Linus Torvalds	16 years
v2.6.32-rc7	commit 156171c71a...	Linus Torvalds	16 years
v2.6.32-rc6	commit b419148e56...	Linus Torvalds	16 years
v2.6.32-rc5	commit 012abeea66...	Linus Torvalds	16 years
v2.6.32-rc4	commit 161291396e...	Linus Torvalds	16 years
v2.6.32-rc3	commit 374576a8b6...	Linus Torvalds	16 years
v2.6.32-rc1	commit 17d857be64...	Linus Torvalds	16 years
v2.6.32-rc2	commit 17d857be64...	Linus Torvalds	16 years
v2.6.31	commit 74fca6a428...	Linus Torvalds	16 years
v2.6.31-rc9	commit e07cccf404...	Linus Torvalds	16 years
v2.6.31-rc8	commit 326ba5010a...	Linus Torvalds	16 years
v2.6.31-rc7	commit 422bef879e...	Linus Torvalds	16 years
v2.6.31-rc6	commit 64f1607ffb...	Linus Torvalds	16 years
v2.6.31-rc5	commit ed680c4ad4...	Linus Torvalds	16 years
v2.6.31-rc4	commit 4be3bd7849...	Linus Torvalds	16 years
v2.6.31-rc3	commit 6847e154e3...	Linus Torvalds	16 years
v2.6.31-rc2	commit 8e4a718ff3...	Linus Torvalds	16 years
v2.6.31-rc1	commit 28d0325ce6...	Linus Torvalds	16 years
v2.6.30	commit 07a2039b8e...	Linus Torvalds	16 years
v2.6.30-rc8	commit 9fa7eb283c...	Linus Torvalds	16 years
v2.6.30-rc7	commit 59a3759d0f...	Linus Torvalds	16 years
v2.6.30-rc6	commit 1406de8e11...	Linus Torvalds	16 years
v2.6.30-rc5	commit 091bf7624d...	Linus Torvalds	16 years
v2.6.30-rc4	commit 091438dd56...	Linus Torvalds	16 years
v2.6.30-rc3	commit 0910697403...	Linus Torvalds	16 years
v2.6.30-rc2	commit 0882e8dd3a...	Linus Torvalds	16 years
v2.6.30-rc1	commit 577c9c456f...	Linus Torvalds	16 years
v2.6.29	commit 8e0ee43bc2...	Linus Torvalds	16 years
v2.6.29-rc8	commit 041b62374c...	Linus Torvalds	17 years
v2.6.29-rc7	commit fec6c6fec3...	Linus Torvalds	17 years
v2.6.29-rc6	commit 20f4d6c3a2...	Linus Torvalds	17 years
v2.6.29-rc5	commit d2f8d7ee1a...	Linus Torvalds	17 years
v2.6.29-rc4	commit 8e4921515c...	Linus Torvalds	17 years
v2.6.29-rc3	commit 18e352e4a7...	Linus Torvalds	17 years
v2.6.29-rc2	commit 1de9e8e70f...	Linus Torvalds	17 years
v2.6.29-rc1	commit c59765042f...	Linus Torvalds	17 years
v2.6.28	commit 4a6908a3a0...	Linus Torvalds	17 years
v2.6.28-rc9	commit 929096fe9f...	Linus Torvalds	17 years
v2.6.28-rc8	commit 8b1fae4e42...	Linus Torvalds	17 years
v2.6.28-rc7	commit 061e41fdb5...	Linus Torvalds	17 years
v2.6.28-rc6	commit 13d428afc0...	Linus Torvalds	17 years
v2.6.28-rc5	commit 9bf1a2445f...	Linus Torvalds	17 years
v2.6.28-rc4	commit f7160c7573...	Linus Torvalds	17 years
v2.6.28-rc3	commit 45beca08dd...	Linus Torvalds	17 years
v2.6.28-rc2	commit 0173a3265b...	Linus Torvalds	17 years
v2.6.28-rc1	commit 57f8f7b60d...	Linus Torvalds	17 years
v2.6.27	commit 3fa8749e58...	Linus Torvalds	17 years
v2.6.27-rc9	commit 4330ed8ed4...	Linus Torvalds	17 years
v2.6.27-rc8	commit 94aca1dac6...	Linus Torvalds	17 years
v2.6.27-rc7	commit 72d31053f6...	Linus Torvalds	17 years
v2.6.27-rc6	commit adee14b2e1...	Linus Torvalds	17 years
v2.6.27-rc5	commit 24342c34a0...	Linus Torvalds	17 years
v2.6.27-rc4	commit 6a55617ed5...	Linus Torvalds	17 years
v2.6.27-rc3	commit 30a2f3c60a...	Linus Torvalds	17 years
v2.6.27-rc2	commit 0967d61ea0...	Linus Torvalds	17 years
v2.6.27-rc1	commit 6e86841d05...	Linus Torvalds	17 years
v2.6.26	commit bce7f793da...	Linus Torvalds	17 years
v2.6.26-rc9	commit b7279469d6...	Linus Torvalds	17 years
v2.6.26-rc8	commit 543cf4cb3f...	Linus Torvalds	17 years
v2.6.26-rc7	commit d70ac829b7...	Linus Torvalds	17 years
v2.6.26-rc6	commit 5dd34572ad...	Linus Torvalds	17 years
v2.6.26-rc5	commit 53c8ba9540...	Linus Torvalds	17 years
v2.6.26-rc4	commit e490517a03...	Linus Torvalds	17 years
v2.6.26-rc3	commit b8291ad07a...	Linus Torvalds	17 years
v2.6.26-rc2	commit 492c2e476e...	Linus Torvalds	17 years
v2.6.26-rc1	commit 2ddcca36c8...	Linus Torvalds	17 years
v2.6.25	commit 4b119e21d0...	Linus Torvalds	17 years
v2.6.25-rc9	commit 120dd64cac...	Linus Torvalds	17 years
v2.6.25-rc8	commit 0e81a8ae37...	Linus Torvalds	17 years
v2.6.25-rc7	commit 05dda977f2...	Linus Torvalds	17 years
v2.6.25-rc6	commit a978b30af3...	Linus Torvalds	17 years
v2.6.25-rc5	commit cdeeeae056...	Linus Torvalds	18 years
v2.6.25-rc4	commit 29e8c3c304...	Linus Torvalds	18 years
v2.6.25-rc3	commit bfa274e243...	Linus Torvalds	18 years
v2.6.25-rc2	commit 101142c37b...	Linus Torvalds	18 years
v2.6.25-rc1	commit 19af35546d...	Linus Torvalds	18 years
v2.6.24	commit 49914084e7...	Linus Torvalds	18 years
v2.6.24-rc8	commit cbd9c88369...	Linus Torvalds	18 years
v2.6.24-rc7	commit 3ce5445046...	Linus Torvalds	18 years
v2.6.24-rc6	commit ea67db4cdb...	Linus Torvalds	18 years
v2.6.24-rc5	commit 82d29bf6dc...	Linus Torvalds	18 years
v2.6.24-rc4	commit 09b56adc98...	Linus Torvalds	18 years
v2.6.24-rc3	commit d9f8bcbf67...	Linus Torvalds	18 years
v2.6.24-rc2	commit dbeeb816e8...	Linus Torvalds	18 years
v2.6.24-rc1	commit c9927c2bf4...	Linus Torvalds	18 years
v2.6.23	commit bbf25010f1...	Linus Torvalds	18 years
v2.6.23-rc9	commit 3146b39c18...	Linus Torvalds	18 years
v2.6.23-rc8	commit 4942de4a0e...	Linus Torvalds	18 years
v2.6.23-rc7	commit 81cfe79b9c...	Linus Torvalds	18 years
v2.6.23-rc6	commit 0d4cbb5e7f...	Linus Torvalds	18 years
v2.6.23-rc5	commit 40ffbfad6b...	Linus Torvalds	18 years
v2.6.23-rc4	commit b07d68b5ca...	Linus Torvalds	18 years
v2.6.23-rc3	commit 39d3520c92...	Linus Torvalds	18 years
v2.6.23-rc2	commit d4ac2477fa...	Linus Torvalds	18 years
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generated by cgit v1.2.2 (git 2.25.0) at 2025-09-09 07:07:15 -0400

/*
 *  linux/fs/ext3/inode.c
 *
 * Copyright (C) 1992, 1993, 1994, 1995
 * Remy Card (card@masi.ibp.fr)
 * Laboratoire MASI - Institut Blaise Pascal
 * Universite Pierre et Marie Curie (Paris VI)
 *
 *  from
 *
 *  linux/fs/minix/inode.c
 *
 *  Copyright (C) 1991, 1992  Linus Torvalds
 *
 *  Goal-directed block allocation by Stephen Tweedie
 *	(sct@redhat.com), 1993, 1998
 *  Big-endian to little-endian byte-swapping/bitmaps by
 *        David S. Miller (davem@caip.rutgers.edu), 1995
 *  64-bit file support on 64-bit platforms by Jakub Jelinek
 *	(jj@sunsite.ms.mff.cuni.cz)
 *
 *  Assorted race fixes, rewrite of ext3_get_block() by Al Viro, 2000
 */

#include <linux/highuid.h>
#include <linux/quotaops.h>
#include <linux/writeback.h>
#include <linux/mpage.h>
#include <linux/namei.h>
#include <linux/uio.h>
#include "ext3.h"
#include "xattr.h"
#include "acl.h"

static int ext3_writepage_trans_blocks(struct inode *inode);
static int ext3_block_truncate_page(struct inode *inode, loff_t from);

/*
 * Test whether an inode is a fast symlink.
 */
static int ext3_inode_is_fast_symlink(struct inode *inode)
{
	int ea_blocks = EXT3_I(inode)->i_file_acl ?
		(inode->i_sb->s_blocksize >> 9) : 0;

	return (S_ISLNK(inode->i_mode) && inode->i_blocks - ea_blocks == 0);
}

/*
 * The ext3 forget function must perform a revoke if we are freeing data
 * which has been journaled.  Metadata (eg. indirect blocks) must be
 * revoked in all cases.
 *
 * "bh" may be NULL: a metadata block may have been freed from memory
 * but there may still be a record of it in the journal, and that record
 * still needs to be revoked.
 */
int ext3_forget(handle_t *handle, int is_metadata, struct inode *inode,
			struct buffer_head *bh, ext3_fsblk_t blocknr)
{
	int err;

	might_sleep();

	trace_ext3_forget(inode, is_metadata, blocknr);
	BUFFER_TRACE(bh, "enter");

	jbd_debug(4, "forgetting bh %p: is_metadata = %d, mode %o, "
		  "data mode %lx\n",
		  bh, is_metadata, inode->i_mode,
		  test_opt(inode->i_sb, DATA_FLAGS));

	/* Never use the revoke function if we are doing full data
	 * journaling: there is no need to, and a V1 superblock won't
	 * support it.  Otherwise, only skip the revoke on un-journaled
	 * data blocks. */

	if (test_opt(inode->i_sb, DATA_FLAGS) == EXT3_MOUNT_JOURNAL_DATA ||
	    (!is_metadata && !ext3_should_journal_data(inode))) {
		if (bh) {
			BUFFER_TRACE(bh, "call journal_forget");
			return ext3_journal_forget(handle, bh);
		}
		return 0;
	}

	/*
	 * data!=journal && (is_metadata || should_journal_data(inode))
	 */
	BUFFER_TRACE(bh, "call ext3_journal_revoke");
	err = ext3_journal_revoke(handle, blocknr, bh);
	if (err)
		ext3_abort(inode->i_sb, __func__,
			   "error %d when attempting revoke", err);
	BUFFER_TRACE(bh, "exit");
	return err;
}

/*
 * Work out how many blocks we need to proceed with the next chunk of a
 * truncate transaction.
 */
static unsigned long blocks_for_truncate(struct inode *inode)
{
	unsigned long needed;

	needed = inode->i_blocks >> (inode->i_sb->s_blocksize_bits - 9);

	/* Give ourselves just enough room to cope with inodes in which
	 * i_blocks is corrupt: we've seen disk corruptions in the past
	 * which resulted in random data in an inode which looked enough
	 * like a regular file for ext3 to try to delete it.  Things
	 * will go a bit crazy if that happens, but at least we should
	 * try not to panic the whole kernel. */
	if (needed < 2)
		needed = 2;

	/* But we need to bound the transaction so we don't overflow the
	 * journal. */
	if (needed > EXT3_MAX_TRANS_DATA)
		needed = EXT3_MAX_TRANS_DATA;

	return EXT3_DATA_TRANS_BLOCKS(inode->i_sb) + needed;
}

/*
 * Truncate transactions can be complex and absolutely huge.  So we need to
 * be able to restart the transaction at a conventient checkpoint to make
 * sure we don't overflow the journal.
 *
 * start_transaction gets us a new handle for a truncate transaction,
 * and extend_transaction tries to extend the existing one a bit.  If
 * extend fails, we need to propagate the failure up and restart the
 * transaction in the top-level truncate loop. --sct
 */
static handle_t *start_transaction(struct inode *inode)
{
	handle_t *result;

	result = ext3_journal_start(inode, blocks_for_truncate(inode));
	if (!IS_ERR(result))
		return result;

	ext3_std_error(inode->i_sb, PTR_ERR(result));
	return result;
}

/*
 * Try to extend this transaction for the purposes of truncation.
 *
 * Returns 0 if we managed to create more room.  If we can't create more
 * room, and the transaction must be restarted we return 1.
 */
static int try_to_extend_transaction(handle_t *handle, struct inode *inode)
{
	if (handle->h_buffer_credits > EXT3_RESERVE_TRANS_BLOCKS)
		return 0;
	if (!ext3_journal_extend(handle, blocks_for_truncate(inode)))
		return 0;
	return 1;
}

/*
 * Restart the transaction associated with *handle.  This does a commit,
 * so before we call here everything must be consistently dirtied against
 * this transaction.
 */
static int truncate_restart_transaction(handle_t *handle, struct inode *inode)
{
	int ret;

	jbd_debug(2, "restarting handle %p\n", handle);
	/*
	 * Drop truncate_mutex to avoid deadlock with ext3_get_blocks_handle
	 * At this moment, get_block can be called only for blocks inside
	 * i_size since page cache has been already dropped and writes are
	 * blocked by i_mutex. So we can safely drop the truncate_mutex.
	 */
	mutex_unlock(&EXT3_I(inode)->truncate_mutex);
	ret = ext3_journal_restart(handle, blocks_for_truncate(inode));
	mutex_lock(&EXT3_I(inode)->truncate_mutex);
	return ret;
}

/*
 * Called at inode eviction from icache
 */
void ext3_evict_inode (struct inode *inode)
{
	struct ext3_inode_info *ei = EXT3_I(inode);
	struct ext3_block_alloc_info *rsv;
	handle_t *handle;
	int want_delete = 0;

	trace_ext3_evict_inode(inode);
	if (!inode->i_nlink && !is_bad_inode(inode)) {
		dquot_initialize(inode);
		want_delete = 1;
	}

	/*
	 * When journalling data dirty buffers are tracked only in the journal.
	 * So although mm thinks everything is clean and ready for reaping the
	 * inode might still have some pages to write in the running
	 * transaction or waiting to be checkpointed. Thus calling
	 * journal_invalidatepage() (via truncate_inode_pages()) to discard
	 * these buffers can cause data loss. Also even if we did not discard
	 * these buffers, we would have no way to find them after the inode
	 * is reaped and thus user could see stale data if he tries to read
	 * them before the transaction is checkpointed. So be careful and
	 * force everything to disk here... We use ei->i_datasync_tid to
	 * store the newest transaction containing inode's data.
	 *
	 * Note that directories do not have this problem because they don't
	 * use page cache.
	 *
	 * The s_journal check handles the case when ext3_get_journal() fails
	 * and puts the journal inode.
	 */
	if (inode->i_nlink && ext3_should_journal_data(inode) &&
	    EXT3_SB(inode->i_sb)->s_journal &&
	    (S_ISLNK(inode->i_mode) || S_ISREG(inode->i_mode)) &&
	    inode->i_ino != EXT3_JOURNAL_INO) {
		tid_t commit_tid = atomic_read(&ei->i_datasync_tid);
		journal_t *journal = EXT3_SB(inode->i_sb)->s_journal;

		log_start_commit(journal, commit_tid);
		log_wait_commit(journal, commit_tid);
		filemap_write_and_wait(&inode->i_data);
	}
	truncate_inode_pages_final(&inode->i_data);

	ext3_discard_reservation(inode);
	rsv = ei->i_block_alloc_info;
	ei->i_block_alloc_info = NULL;
	if (unlikely(rsv))
		kfree(rsv);

	if (!want_delete)
		goto no_delete;

	handle = start_transaction(inode);
	if (IS_ERR(handle)) {
		/*
		 * If we're going to skip the normal cleanup, we still need to
		 * make sure that the in-core orphan linked list is properly
		 * cleaned up.
		 */
		ext3_orphan_del(NULL, inode);
		goto no_delete;
	}

	if (IS_SYNC(inode))
		handle->h_sync = 1;
	inode->i_size = 0;
	if (inode->i_blocks)
		ext3_truncate(inode);
	/*
	 * Kill off the orphan record created when the inode lost the last
	 * link.  Note that ext3_orphan_del() has to be able to cope with the
	 * deletion of a non-existent orphan - ext3_truncate() could
	 * have removed the record.
	 */
	ext3_orphan_del(handle, inode);
	ei->i_dtime = get_seconds();

	/*
	 * One subtle ordering requirement: if anything has gone wrong
	 * (transaction abort, IO errors, whatever), then we can still
	 * do these next steps (the fs will already have been marked as
	 * having errors), but we can't free the inode if the mark_dirty
	 * fails.
	 */
	if (ext3_mark_inode_dirty(handle, inode)) {
		/* If that failed, just dquot_drop() and be done with that */
		dquot_drop(inode);
		clear_inode(inode);
	} else {
		ext3_xattr_delete_inode(handle, inode);
		dquot_free_inode(inode);
		dquot_drop(inode);
		clear_inode(inode);
		ext3_free_inode(handle, inode);
	}
	ext3_journal_stop(handle);
	return;
no_delete:
	clear_inode(inode);
	dquot_drop(inode);
}

typedef struct {
	__le32	*p;
	__le32	key;
	struct buffer_head *bh;
} Indirect;

static inline void add_chain(Indirect *p, struct buffer_head *bh, __le32 *v)
{
	p->key = *(p->p = v);
	p->bh = bh;
}

static int verify_chain(Indirect *from, Indirect *to)
{
	while (from <= to && from->key == *from->p)
		from++;
	return (from > to);
}

/**
 *	ext3_block_to_path - parse the block number into array of offsets
 *	@inode: inode in question (we are only interested in its superblock)
 *	@i_block: block number to be parsed
 *	@offsets: array to store the offsets in
 *      @boundary: set this non-zero if the referred-to block is likely to be
 *             followed (on disk) by an indirect block.
 *
 *	To store the locations of file's data ext3 uses a data structure common
 *	for UNIX filesystems - tree of pointers anchored in the inode, with
 *	data blocks at leaves and indirect blocks in intermediate nodes.
 *	This function translates the block number into path in that tree -
 *	return value is the path length and @offsets[n] is the offset of
 *	pointer to (n+1)th node in the nth one. If @block is out of range
 *	(negative or too large) warning is printed and zero returned.
 *
 *	Note: function doesn't find node addresses, so no IO is needed. All
 *	we need to know is the capacity of indirect blocks (taken from the
 *	inode->i_sb).
 */

/*
 * Portability note: the last comparison (check that we fit into triple
 * indirect block) is spelled differently, because otherwise on an
 * architecture with 32-bit longs and 8Kb pages we might get into trouble
 * if our filesystem had 8Kb blocks. We might use long long, but that would
 * kill us on x86. Oh, well, at least the sign propagation does not matter -
 * i_block would have to be negative in the very beginning, so we would not
 * get there at all.
 */

static int ext3_block_to_path(struct inode *inode,
			long i_block, int offsets[4], int *boundary)
{
	int ptrs = EXT3_ADDR_PER_BLOCK(inode->i_sb);
	int ptrs_bits = EXT3_ADDR_PER_BLOCK_BITS(inode->i_sb);
	const long direct_blocks = EXT3_NDIR_BLOCKS,
		indirect_blocks = ptrs,
		double_blocks = (1 << (ptrs_bits * 2));
	int n = 0;
	int final = 0;

	if (i_block < 0) {
		ext3_warning (inode->i_sb, "ext3_block_to_path", "block < 0");
	} else if (i_block < direct_blocks) {
		offsets[n++] = i_block;
		final = direct_blocks;
	} else if ( (i_block -= direct_blocks) < indirect_blocks) {
		offsets[n++] = EXT3_IND_BLOCK;
		offsets[n++] = i_block;
		final = ptrs;
	} else if ((i_block -= indirect_blocks) < double_blocks) {
		offsets[n++] = EXT3_DIND_BLOCK;
		offsets[n++] = i_block >> ptrs_bits;
		offsets[n++] = i_block & (ptrs - 1);
		final = ptrs;
	} else if (((i_block -= double_blocks) >> (ptrs_bits * 2)) < ptrs) {
		offsets[n++] = EXT3_TIND_BLOCK;
		offsets[n++] = i_block >> (ptrs_bits * 2);
		offsets[n++] = (i_block >> ptrs_bits) & (ptrs - 1);
		offsets[n++] = i_block & (ptrs - 1);
		final = ptrs;
	} else {
		ext3_warning(inode->i_sb, "ext3_block_to_path", "block > big");
	}
	if (boundary)
		*boundary = final - 1 - (i_block & (ptrs - 1));
	return n;
}

/**
 *	ext3_get_branch - read the chain of indirect blocks leading to data
 *	@inode: inode in question
 *	@depth: depth of the chain (1 - direct pointer, etc.)
 *	@offsets: offsets of pointers in inode/indirect blocks
 *	@chain: place to store the result
 *	@err: here we store the error value
 *
 *	Function fills the array of triples <key, p, bh> and returns %NULL
 *	if everything went OK or the pointer to the last filled triple
 *	(incomplete one) otherwise. Upon the return chain[i].key contains
 *	the number of (i+1)-th block in the chain (as it is stored in memory,
 *	i.e. little-endian 32-bit), chain[i].p contains the address of that
 *	number (it points into struct inode for i==0 and into the bh->b_data
 *	for i>0) and chain[i].bh points to the buffer_head of i-th indirect
 *	block for i>0 and NULL for i==0. In other words, it holds the block
 *	numbers of the chain, addresses they were taken from (and where we can
 *	verify that chain did not change) and buffer_heads hosting these
 *	numbers.
 *
 *	Function stops when it stumbles upon zero pointer (absent block)
 *		(pointer to last triple returned, *@err == 0)
 *	or when it gets an IO error reading an indirect block
 *		(ditto, *@err == -EIO)
 *	or when it notices that chain had been changed while it was reading
 *		(ditto, *@err == -EAGAIN)
 *	or when it reads all @depth-1 indirect blocks successfully and finds
 *	the whole chain, all way to the data (returns %NULL, *err == 0).
 */
static Indirect *ext3_get_branch(struct inode *inode, int depth, int *offsets,
				 Indirect chain[4], int *err)
{
	struct super_block *sb = inode->i_sb;
	Indirect *p = chain;
	struct buffer_head *bh;

	*err = 0;
	/* i_data is not going away, no lock needed */
	add_chain (chain, NULL, EXT3_I(inode)->i_data + *offsets);
	if (!p->key)
		goto no_block;
	while (--depth) {
		bh = sb_bread(sb, le32_to_cpu(p->key));
		if (!bh)
			goto failure;
		/* Reader: pointers */
		if (!verify_chain(chain, p))
			goto changed;
		add_chain(++p, bh, (__le32*)bh->b_data + *++offsets);
		/* Reader: end */
		if (!p->key)
			goto no_block;
	}
	return NULL;

changed:
	brelse(bh);
	*err = -EAGAIN;
	goto no_block;
failure:
	*err = -EIO;
no_block:
	return p;
}

/**
 *	ext3_find_near - find a place for allocation with sufficient locality
 *	@inode: owner
 *	@ind: descriptor of indirect block.
 *
 *	This function returns the preferred place for block allocation.
 *	It is used when heuristic for sequential allocation fails.
 *	Rules are:
 *	  + if there is a block to the left of our position - allocate near it.
 *	  + if pointer will live in indirect block - allocate near that block.
 *	  + if pointer will live in inode - allocate in the same
 *	    cylinder group.
 *
 * In the latter case we colour the starting block by the callers PID to
 * prevent it from clashing with concurrent allocations for a different inode
 * in the same block group.   The PID is used here so that functionally related
 * files will be close-by on-disk.
 *
 *	Caller must make sure that @ind is valid and will stay that way.
 */
static ext3_fsblk_t ext3_find_near(struct inode *inode, Indirect *ind)
{
	struct ext3_inode_info *ei = EXT3_I(inode);
	__le32 *start = ind->bh ? (__le32*) ind->bh->b_data : ei->i_data;
	__le32 *p;
	ext3_fsblk_t bg_start;
	ext3_grpblk_t colour;

	/* Try to find previous block */
	for (p = ind->p - 1; p >= start; p--) {
		if (*p)
			return le32_to_cpu(*p);
	}

	/* No such thing, so let's try location of indirect block */
	if (ind->bh)
		return ind->bh->b_blocknr;

	/*
	 * It is going to be referred to from the inode itself? OK, just put it
	 * into the same cylinder group then.
	 */
	bg_start = ext3_group_first_block_no(inode->i_sb, ei->i_block_group);
	colour = (current->pid % 16) *
			(EXT3_BLOCKS_PER_GROUP(inode->i_sb) / 16);
	return bg_start + colour;
}

/**
 *	ext3_find_goal - find a preferred place for allocation.
 *	@inode: owner
 *	@block:  block we want
 *	@partial: pointer to the last triple within a chain
 *
 *	Normally this function find the preferred place for block allocation,
 *	returns it.
 */

static ext3_fsblk_t ext3_find_goal(struct inode *inode, long block,
				   Indirect *partial)
{
	struct ext3_block_alloc_info *block_i;

	block_i =  EXT3_I(inode)->i_block_alloc_info;

	/*
	 * try the heuristic for sequential allocation,
	 * failing that at least try to get decent locality.
	 */
	if (block_i && (block == block_i->last_alloc_logical_block + 1)
		&& (block_i->last_alloc_physical_block != 0)) {
		return block_i->last_alloc_physical_block + 1;
	}

	return ext3_find_near(inode, partial);
}

/**
 *	ext3_blks_to_allocate - Look up the block map and count the number
 *	of direct blocks need to be allocated for the given branch.
 *
 *	@branch: chain of indirect blocks
 *	@k: number of blocks need for indirect blocks
 *	@blks: number of data blocks to be mapped.
 *	@blocks_to_boundary:  the offset in the indirect block
 *
 *	return the total number of blocks to be allocate, including the
 *	direct and indirect blocks.
 */
static int ext3_blks_to_allocate(Indirect *branch, int k, unsigned long blks,
		int blocks_to_boundary)
{
	unsigned long count = 0;

	/*
	 * Simple case, [t,d]Indirect block(s) has not allocated yet
	 * then it's clear blocks on that path have not allocated
	 */
	if (k > 0) {
		/* right now we don't handle cross boundary allocation */
		if (blks < blocks_to_boundary + 1)
			count += blks;
		else
			count += blocks_to_boundary + 1;
		return count;
	}

	count++;
	while (count < blks && count <= blocks_to_boundary &&
		le32_to_cpu(*(branch[0].p + count)) == 0) {
		count++;
	}
	return count;
}

/**
 *	ext3_alloc_blocks - multiple allocate blocks needed for a branch
 *	@handle: handle for this transaction
 *	@inode: owner
 *	@goal: preferred place for allocation
 *	@indirect_blks: the number of blocks need to allocate for indirect
 *			blocks
 *	@blks:	number of blocks need to allocated for direct blocks
 *	@new_blocks: on return it will store the new block numbers for
 *	the indirect blocks(if needed) and the first direct block,
 *	@err: here we store the error value
 *
 *	return the number of direct blocks allocated
 */
static int ext3_alloc_blocks(handle_t *handle, struct inode *inode,
			ext3_fsblk_t goal, int indirect_blks, int blks,
			ext3_fsblk_t new_blocks[4], int *err)
{
	int target, i;
	unsigned long count = 0;
	int index = 0;
	ext3_fsblk_t current_block = 0;
	int ret = 0;

	/*
	 * Here we try to allocate the requested multiple blocks at once,
	 * on a best-effort basis.
	 * To build a branch, we should allocate blocks for
	 * the indirect blocks(if not allocated yet), and at least
	 * the first direct block of this branch.  That's the
	 * minimum number of blocks need to allocate(required)
	 */
	target = blks + indirect_blks;

	while (1) {
		count = target;
		/* allocating blocks for indirect blocks and direct blocks */
		current_block = ext3_new_blocks(handle,inode,goal,&count,err);
		if (*err)
			goto failed_out;

		target -= count;
		/* allocate blocks for indirect blocks */
		while (index < indirect_blks && count) {
			new_blocks[index++] = current_block++;
			count--;
		}

		if (count > 0)
			break;
	}

	/* save the new block number for the first direct block */
	new_blocks[index] = current_block;

	/* total number of blocks allocated for direct blocks */
	ret = count;
	*err = 0;
	return ret;
failed_out:
	for (i = 0; i <index; i++)
		ext3_free_blocks(handle, inode, new_blocks[i], 1);
	return ret;
}

/**
 *	ext3_alloc_branch - allocate and set up a chain of blocks.
 *	@handle: handle for this transaction
 *	@inode: owner
 *	@indirect_blks: number of allocated indirect blocks
 *	@blks: number of allocated direct blocks
 *	@goal: preferred place for allocation
 *	@offsets: offsets (in the blocks) to store the pointers to next.
 *	@branch: place to store the chain in.
 *
 *	This function allocates blocks, zeroes out all but the last one,
 *	links them into chain and (if we are synchronous) writes them to disk.
 *	In other words, it prepares a branch that can be spliced onto the
 *	inode. It stores the information about that chain in the branch[], in
 *	the same format as ext3_get_branch() would do. We are calling it after
 *	we had read the existing part of chain and partial points to the last
 *	triple of that (one with zero ->key). Upon the exit we have the same
 *	picture as after the successful ext3_get_block(), except that in one
 *	place chain is disconnected - *branch->p is still zero (we did not
 *	set the last link), but branch->key contains the number that should
 *	be placed into *branch->p to fill that gap.
 *
 *	If allocation fails we free all blocks we've allocated (and forget
 *	their buffer_heads) and return the error value the from failed
 *	ext3_alloc_block() (normally -ENOSPC). Otherwise we set the chain
 *	as described above and return 0.
 */
static int ext3_alloc_branch(handle_t *handle, struct inode *inode,
			int indirect_blks, int *blks, ext3_fsblk_t goal,
			int *offsets, Indirect *branch)
{
	int blocksize = inode->i_sb->s_blocksize;
	int i, n = 0;
	int err = 0;
	struct buffer_head *bh;
	int num;
	ext3_fsblk_t new_blocks[4];
	ext3_fsblk_t current_block;

	num = ext3_alloc_blocks(handle, inode, goal, indirect_blks,
				*blks, new_blocks, &err);
	if (err)
		return err;

	branch[0].key = cpu_to_le32(new_blocks[0]);
	/*
	 * metadata blocks and data blocks are allocated.
	 */
	for (n = 1; n <= indirect_blks;  n++) {
		/*
		 * Get buffer_head for parent block, zero it out
		 * and set the pointer to new one, then send
		 * parent to disk.
		 */
		bh = sb_getblk(inode->i_sb, new_blocks[n-1]);
		if (unlikely(!bh)) {
			err = -ENOMEM;
			goto failed;
		}
		branch[n].bh = bh;
		lock_buffer(bh);
		BUFFER_TRACE(bh, "call get_create_access");
		err = ext3_journal_get_create_access(handle, bh);
		if (err) {
			unlock_buffer(bh);
			brelse(bh);
			goto failed;
		}

		memset(bh->b_data, 0, blocksize);
		branch[n].p = (__le32 *) bh->b_data + offsets[n];
		branch[n].key = cpu_to_le32(new_blocks[n]);
		*branch[n].p = branch[n].key;
		if ( n == indirect_blks) {
			current_block = new_blocks[n];
			/*
			 * End of chain, update the last new metablock of
			 * the chain to point to the new allocated
			 * data blocks numbers
			 */
			for (i=1; i < num; i++)
				*(branch[n].p + i) = cpu_to_le32(++current_block);
		}
		BUFFER_TRACE(bh, "marking uptodate");
		set_buffer_uptodate(bh);
		unlock_buffer(bh);

		BUFFER_TRACE(bh, "call ext3_journal_dirty_metadata");
		err = ext3_journal_dirty_metadata(handle, bh);
		if (err)
			goto failed;
	}
	*blks = num;
	return err;
failed:
	/* Allocation failed, free what we already allocated */
	for (i = 1; i <= n ; i++) {
		BUFFER_TRACE(branch[i].bh, "call journal_forget");
		ext3_journal_forget(handle, branch[i].bh);
	}
	for (i = 0; i < indirect_blks; i++)
		ext3_free_blocks(handle, inode, new_blocks[i], 1);

	ext3_free_blocks(handle, inode, new_blocks[i], num);

	return err;
}

/**
 * ext3_splice_branch - splice the allocated branch onto inode.
 * @handle: handle for this transaction
 * @inode: owner
 * @block: (logical) number of block we are adding
 * @where: location of missing link
 * @num:   number of indirect blocks we are adding
 * @blks:  number of direct blocks we are adding
 *
 * This function fills the missing link and does all housekeeping needed in
 * inode (->i_blocks, etc.). In case of success we end up with the full
 * chain to new block and return 0.
 */
static int ext3_splice_branch(handle_t *handle, struct inode *inode,
			long block, Indirect *where, int num, int blks)
{
	int i;
	int err = 0;
	struct ext3_block_alloc_info *block_i;
	ext3_fsblk_t current_block;
	struct ext3_inode_info *ei = EXT3_I(inode);
	struct timespec now;

	block_i = ei->i_block_alloc_info;
	/*
	 * If we're splicing into a [td]indirect block (as opposed to the
	 * inode) then we need to get write access to the [td]indirect block
	 * before the splice.
	 */
	if (where->bh) {
		BUFFER_TRACE(where->bh, "get_write_access");
		err = ext3_journal_get_write_access(handle, where->bh);
		if (err)
			goto err_out;
	}
	/* That's it */

	*where->p = where->key;

	/*
	 * Update the host buffer_head or inode to point to more just allocated
	 * direct blocks blocks
	 */
	if (num == 0 && blks > 1) {
		current_block = le32_to_cpu(where->key) + 1;
		for (i = 1; i < blks; i++)
			*(where->p + i ) = cpu_to_le32(current_block++);
	}

	/*
	 * update the most recently allocated logical & physical block
	 * in i_block_alloc_info, to assist find the proper goal block for next
	 * allocation
	 */
	if (block_i) {
		block_i->last_alloc_logical_block = block + blks - 1;
		block_i->last_alloc_physical_block =
				le32_to_cpu(where[num].key) + blks - 1;
	}

	/* We are done with atomic stuff, now do the rest of housekeeping */
	now = CURRENT_TIME_SEC;
	if (!timespec_equal(&inode->i_ctime, &now) || !where->bh) {
		inode->i_ctime = now;
		ext3_mark_inode_dirty(handle, inode);
	}
	/* ext3_mark_inode_dirty already updated i_sync_tid */
	atomic_set(&ei->i_datasync_tid, handle->h_transaction->t_tid);

	/* had we spliced it onto indirect block? */
	if (where->bh) {
		/*
		 * If we spliced it onto an indirect block, we haven't
		 * altered the inode.  Note however that if it is being spliced
		 * onto an indirect block at the very end of the file (the
		 * file is growing) then we *will* alter the inode to reflect
		 * the new i_size.  But that is not done here - it is done in
		 * generic_commit_write->__mark_inode_dirty->ext3_dirty_inode.
		 */
		jbd_debug(5, "splicing indirect only\n");
		BUFFER_TRACE(where->bh, "call ext3_journal_dirty_metadata");
		err = ext3_journal_dirty_metadata(handle, where->bh);
		if (err)
			goto err_out;
	} else {
		/*
		 * OK, we spliced it into the inode itself on a direct block.
		 * Inode was dirtied above.
		 */
		jbd_debug(5, "splicing direct\n");
	}
	return err;

err_out:
	for (i = 1; i <= num; i++) {
		BUFFER_TRACE(where[i].bh, "call journal_forget");
		ext3_journal_forget(handle, where[i].bh);
		ext3_free_blocks(handle,inode,le32_to_cpu(where[i-1].key),1);
	}
	ext3_free_blocks(handle, inode, le32_to_cpu(where[num].key), blks);

	return err;
}

/*
 * Allocation strategy is simple: if we have to allocate something, we will
 * have to go the whole way to leaf. So let's do it before attaching anything
 * to tree, set linkage between the newborn blocks, write them if sync is
 * required, recheck the path, free and repeat if check fails, otherwise
 * set the last missing link (that will protect us from any truncate-generated
 * removals - all blocks on the path are immune now) and possibly force the
 * write on the parent block.
 * That has a nice additional property: no special recovery from the failed
 * allocations is needed - we simply release blocks and do not touch anything
 * reachable from inode.
 *
 * `handle' can be NULL if create == 0.
 *
 * The BKL may not be held on entry here.  Be sure to take it early.
 * return > 0, # of blocks mapped or allocated.
 * return = 0, if plain lookup failed.
 * return < 0, error case.
 */
int ext3_get_blocks_handle(handle_t *handle, struct inode *inode,
		sector_t iblock, unsigned long maxblocks,
		struct buffer_head *bh_result,
		int create)
{
	int err = -EIO;
	int offsets[4];
	Indirect chain[4];
	Indirect *partial;
	ext3_fsblk_t goal;
	int indirect_blks;
	int blocks_to_boundary = 0;
	int depth;
	struct ext3_inode_info *ei = EXT3_I(inode);
	int count = 0;
	ext3_fsblk_t first_block = 0;


	trace_ext3_get_blocks_enter(inode, iblock, maxblocks, create);
	J_ASSERT(handle != NULL || create == 0);
	depth = ext3_block_to_path(inode,iblock,offsets,&blocks_to_boundary);

	if (depth == 0)
		goto out;

	partial = ext3_get_branch(inode, depth, offsets, chain, &err);

	/* Simplest case - block found, no allocation needed */
	if (!partial) {
		first_block = le32_to_cpu(chain[depth - 1].key);
		clear_buffer_new(bh_result);
		count++;
		/*map more blocks*/
		while (count < maxblocks && count <= blocks_to_boundary) {
			ext3_fsblk_t blk;

			if (!verify_chain(chain, chain + depth - 1)) {
				/*
				 * Indirect block might be removed by
				 * truncate while we were reading it.
				 * Handling of that case: forget what we've
				 * got now. Flag the err as EAGAIN, so it
				 * will reread.
				 */
				err = -EAGAIN;
				count = 0;
				break;
			}
			blk = le32_to_cpu(*(chain[depth-1].p + count));

			if (blk == first_block + count)
				count++;
			else
				break;
		}
		if (err != -EAGAIN)
			goto got_it;
	}

	/* Next simple case - plain lookup or failed read of indirect block */
	if (!create || err == -EIO)
		goto cleanup;

	/*
	 * Block out ext3_truncate while we alter the tree
	 */
	mutex_lock(&ei->truncate_mutex);

	/*
	 * If the indirect block is missing while we are reading
	 * the chain(ext3_get_branch() returns -EAGAIN err), or
	 * if the chain has been changed after we grab the semaphore,
	 * (either because another process truncated this branch, or
	 * another get_block allocated this branch) re-grab the chain to see if
	 * the request block has been allocated or not.
	 *
	 * Since we already block the truncate/other get_block
	 * at this point, we will have the current copy of the chain when we
	 * splice the branch into the tree.
	 */
	if (err == -EAGAIN || !verify_chain(chain, partial)) {
		while (partial > chain) {
			brelse(partial->bh);
			partial--;
		}
		partial = ext3_get_branch(inode, depth, offsets, chain, &err);
		if (!partial) {
			count++;
			mutex_unlock(&ei->truncate_mutex);
			if (err)
				goto cleanup;
			clear_buffer_new(bh_result);
			goto got_it;
		}
	}

	/*
	 * Okay, we need to do block allocation.  Lazily initialize the block
	 * allocation info here if necessary
	*/
	if (S_ISREG(inode->i_mode) && (!ei->i_block_alloc_info))
		ext3_init_block_alloc_info(inode);

	goal = ext3_find_goal(inode, iblock, partial);

	/* the number of blocks need to allocate for [d,t]indirect blocks */
	indirect_blks = (chain + depth) - partial - 1;

	/*
	 * Next look up the indirect map to count the totoal number of
	 * direct blocks to allocate for this branch.
	 */
	count = ext3_blks_to_allocate(partial, indirect_blks,
					maxblocks, blocks_to_boundary);
	err = ext3_alloc_branch(handle, inode, indirect_blks, &count, goal,
				offsets + (partial - chain), partial);

	/*
	 * The ext3_splice_branch call will free and forget any buffers
	 * on the new chain if there is a failure, but that risks using
	 * up transaction credits, especially for bitmaps where the
	 * credits cannot be returned.  Can we handle this somehow?  We
	 * may need to return -EAGAIN upwards in the worst case.  --sct
	 */
	if (!err)
		err = ext3_splice_branch(handle, inode, iblock,
					partial, indirect_blks, count);
	mutex_unlock(&ei->truncate_mutex);
	if (err)
		goto cleanup;

	set_buffer_new(bh_result);
got_it:
	map_bh(bh_result, inode->i_sb, le32_to_cpu(chain[depth-1].key));
	if (count > blocks_to_boundary)
		set_buffer_boundary(bh_result);
	err = count;
	/* Clean up and exit */
	partial = chain + depth - 1;	/* the whole chain */
cleanup:
	while (partial > chain) {
		BUFFER_TRACE(partial->bh, "call brelse");
		brelse(partial->bh);
		partial--;
	}
	BUFFER_TRACE(bh_result, "returned");
out:
	trace_ext3_get_blocks_exit(inode, iblock,
				   depth ? le32_to_cpu(chain[depth-1].key) : 0,
				   count, err);
	return err;
}

/* Maximum number of blocks we map for direct IO at once. */
#define DIO_MAX_BLOCKS 4096
/*
 * Number of credits we need for writing DIO_MAX_BLOCKS:
 * We need sb + group descriptor + bitmap + inode -> 4
 * For B blocks with A block pointers per block we need:
 * 1 (triple ind.) + (B/A/A + 2) (doubly ind.) + (B/A + 2) (indirect).
 * If we plug in 4096 for B and 256 for A (for 1KB block size), we get 25.
 */
#define DIO_CREDITS 25

static int ext3_get_block(struct inode *inode, sector_t iblock,
			struct buffer_head *bh_result, int create)
{
	handle_t *handle = ext3_journal_current_handle();
	int ret = 0, started = 0;
	unsigned max_blocks = bh_result->b_size >> inode->i_blkbits;

	if (create && !handle) {	/* Direct IO write... */
		if (max_blocks > DIO_MAX_BLOCKS)
			max_blocks = DIO_MAX_BLOCKS;
		handle = ext3_journal_start(inode, DIO_CREDITS +
				EXT3_MAXQUOTAS_TRANS_BLOCKS(inode->i_sb));
		if (IS_ERR(handle)) {
			ret = PTR_ERR(handle);
			goto out;
		}
		started = 1;
	}

	ret = ext3_get_blocks_handle(handle, inode, iblock,
					max_blocks, bh_result, create);
	if (ret > 0) {
		bh_result->b_size = (ret << inode->i_blkbits);
		ret = 0;
	}
	if (started)
		ext3_journal_stop(handle);
out:
	return ret;
}

int ext3_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
		u64 start, u64 len)
{
	return generic_block_fiemap(inode, fieinfo, start, len,
				    ext3_get_block);
}

/*
 * `handle' can be NULL if create is zero
 */
struct buffer_head *ext3_getblk(handle_t *handle, struct inode *inode,
				long block, int create, int *errp)
{
	struct buffer_head dummy;
	int fatal = 0, err;

	J_ASSERT(handle != NULL || create == 0);

	dummy.b_state = 0;
	dummy.b_blocknr = -1000;
	buffer_trace_init(&dummy.b_history);
	err = ext3_get_blocks_handle(handle, inode, block, 1,
					&dummy, create);
	/*
	 * ext3_get_blocks_handle() returns number of blocks
	 * mapped. 0 in case of a HOLE.
	 */
	if (err > 0) {
		WARN_ON(err > 1);
		err = 0;
	}
	*errp = err;
	if (!err && buffer_mapped(&dummy)) {
		struct buffer_head *bh;
		bh = sb_getblk(inode->i_sb, dummy.b_blocknr);
		if (unlikely(!bh)) {
			*errp = -ENOMEM;
			goto err;
		}
		if (buffer_new(&dummy)) {
			J_ASSERT(create != 0);
			J_ASSERT(handle != NULL);

			/*
			 * Now that we do not always journal data, we should
			 * keep in mind whether this should always journal the
			 * new buffer as metadata.  For now, regular file
			 * writes use ext3_get_block instead, so it's not a
			 * problem.
			 */
			lock_buffer(bh);
			BUFFER_TRACE(bh, "call get_create_access");
			fatal = ext3_journal_get_create_access(handle, bh);
			if (!fatal && !buffer_uptodate(bh)) {
				memset(bh->b_data,0,inode->i_sb->s_blocksize);
				set_buffer_uptodate(bh);
			}
			unlock_buffer(bh);
			BUFFER_TRACE(bh, "call ext3_journal_dirty_metadata");
			err = ext3_journal_dirty_metadata(handle, bh);
			if (!fatal)
				fatal = err;
		} else {
			BUFFER_TRACE(bh, "not a new buffer");
		}
		if (fatal) {
			*errp = fatal;
			brelse(bh);
			bh = NULL;
		}
		return bh;
	}
err:
	return NULL;
}

struct buffer_head *ext3_bread(handle_t *handle, struct inode *inode,
			       int block, int create, int *err)
{
	struct buffer_head * bh;

	bh = ext3_getblk(handle, inode, block, create, err);
	if (!bh)
		return bh;
	if (bh_uptodate_or_lock(bh))
		return bh;
	get_bh(bh);
	bh->b_end_io = end_buffer_read_sync;
	submit_bh(READ | REQ_META | REQ_PRIO, bh);
	wait_on_buffer(bh);
	if (buffer_uptodate(bh))
		return bh;
	put_bh(bh);
	*err = -EIO;
	return NULL;
}

static int walk_page_buffers(	handle_t *handle,
				struct buffer_head *head,
				unsigned from,
				unsigned to,
				int *partial,
				int (*fn)(	handle_t *handle,
						struct buffer_head *bh))
{
	struct buffer_head *bh;
	unsigned block_start, block_end;
	unsigned blocksize = head->b_size;
	int err, ret = 0;
	struct buffer_head *next;

	for (	bh = head, block_start = 0;
		ret == 0 && (bh != head || !block_start);
		block_start = block_end, bh = next)
	{
		next = bh->b_this_page;
		block_end = block_start + blocksize;
		if (block_end <= from || block_start >= to) {
			if (partial && !buffer_uptodate(bh))
				*partial = 1;
			continue;
		}
		err = (*fn)(handle, bh);
		if (!ret)
			ret = err;
	}
	return ret;
}

/*
 * To preserve ordering, it is essential that the hole instantiation and
 * the data write be encapsulated in a single transaction.  We cannot
 * close off a transaction and start a new one between the ext3_get_block()
 * and the commit_write().  So doing the journal_start at the start of
 * prepare_write() is the right place.
 *
 * Also, this function can nest inside ext3_writepage() ->
 * block_write_full_page(). In that case, we *know* that ext3_writepage()
 * has generated enough buffer credits to do the whole page.  So we won't
 * block on the journal in that case, which is good, because the caller may
 * be PF_MEMALLOC.
 *
 * By accident, ext3 can be reentered when a transaction is open via
 * quota file writes.  If we were to commit the transaction while thus
 * reentered, there can be a deadlock - we would be holding a quota
 * lock, and the commit would never complete if another thread had a
 * transaction open and was blocking on the quota lock - a ranking
 * violation.
 *
 * So what we do is to rely on the fact that journal_stop/journal_start
 * will _not_ run commit under these circumstances because handle->h_ref
 * is elevated.  We'll still have enough credits for the tiny quotafile
 * write.
 */
static int do_journal_get_write_access(handle_t *handle,
					struct buffer_head *bh)
{
	int dirty = buffer_dirty(bh);
	int ret;

	if (!buffer_mapped(bh) || buffer_freed(bh))
		return 0;
	/*
	 * __block_prepare_write() could have dirtied some buffers. Clean
	 * the dirty bit as jbd2_journal_get_write_access() could complain
	 * otherwise about fs integrity issues. Setting of the dirty bit
	 * by __block_prepare_write() isn't a real problem here as we clear
	 * the bit before releasing a page lock and thus writeback cannot
	 * ever write the buffer.
	 */
	if (dirty)
		clear_buffer_dirty(bh);
	ret = ext3_journal_get_write_access(handle, bh);
	if (!ret && dirty)
		ret = ext3_journal_dirty_metadata(handle, bh);
	return ret;
}

/*
 * Truncate blocks that were not used by write. We have to truncate the
 * pagecache as well so that corresponding buffers get properly unmapped.
 */
static void ext3_truncate_failed_write(struct inode *inode)
{
	truncate_inode_pages(inode->i_mapping, inode->i_size);
	ext3_truncate(inode);
}

/*
 * Truncate blocks that were not used by direct IO write. We have to zero out
 * the last file block as well because direct IO might have written to it.
 */
static void ext3_truncate_failed_direct_write(struct inode *inode)
{
	ext3_block_truncate_page(inode, inode->i_size);
	ext3_truncate(inode);
}

static int ext3_write_begin(struct file *file, struct address_space *mapping,
				loff_t pos, unsigned len, unsigned flags,
				struct page **pagep, void **fsdata)
{
	struct inode *inode = mapping->host;
	int ret;
	handle_t *handle;
	int retries = 0;
	struct page *page;
	pgoff_t index;
	unsigned from, to;
	/* Reserve one block more for addition to orphan list in case
	 * we allocate blocks but write fails for some reason */
	int needed_blocks = ext3_writepage_trans_blocks(inode) + 1;

	trace_ext3_write_begin(inode, pos, len, flags);

	index = pos >> PAGE_CACHE_SHIFT;
	from = pos & (PAGE_CACHE_SIZE - 1);
	to = from + len;

retry:
	page = grab_cache_page_write_begin(mapping, index, flags);
	if (!page)
		return -ENOMEM;
	*pagep = page;

	handle = ext3_journal_start(inode, needed_blocks);
	if (IS_ERR(handle)) {
		unlock_page(page);
		page_cache_release(page);
		ret = PTR_ERR(handle);
		goto out;
	}
	ret = __block_write_begin(page, pos, len, ext3_get_block);
	if (ret)
		goto write_begin_failed;

	if (ext3_should_journal_data(inode)) {
		ret = walk_page_buffers(handle, page_buffers(page),
				from, to, NULL, do_journal_get_write_access);
	}
write_begin_failed:
	if (ret) {
		/*
		 * block_write_begin may have instantiated a few blocks
		 * outside i_size.  Trim these off again. Don't need
		 * i_size_read because we hold i_mutex.
		 *
		 * Add inode to orphan list in case we crash before truncate
		 * finishes. Do this only if ext3_can_truncate() agrees so
		 * that orphan processing code is happy.
		 */
		if (pos + len > inode->i_size && ext3_can_truncate(inode))
			ext3_orphan_add(handle, inode);
		ext3_journal_stop(handle);
		unlock_page(page);
		page_cache_release(page);
		if (pos + len > inode->i_size)
			ext3_truncate_failed_write(inode);
	}
	if (ret == -ENOSPC && ext3_should_retry_alloc(inode->i_sb, &retries))
		goto retry;
out:
	return ret;
}


int ext3_journal_dirty_data(handle_t *handle, struct buffer_head *bh)
{
	int err = journal_dirty_data(handle, bh);
	if (err)
		ext3_journal_abort_handle(__func__, __func__,
						bh, handle, err);
	return err;
}

/* For ordered writepage and write_end functions */
static int journal_dirty_data_fn(handle_t *handle, struct buffer_head *bh)
{
	/*
	 * Write could have mapped the buffer but it didn't copy the data in
	 * yet. So avoid filing such buffer into a transaction.
	 */
	if (buffer_mapped(bh) && buffer_uptodate(bh))
		return ext3_journal_dirty_data(handle, bh);
	return 0;
}

/* For write_end() in data=journal mode */
static int write_end_fn(handle_t *handle, struct buffer_head *bh)
{
	if (!buffer_mapped(bh) || buffer_freed(bh))
		return 0;
	set_buffer_uptodate(bh);
	return ext3_journal_dirty_metadata(handle, bh);
}

/*
 * This is nasty and subtle: ext3_write_begin() could have allocated blocks
 * for the whole page but later we failed to copy the data in. Update inode
 * size according to what we managed to copy. The rest is going to be
 * truncated in write_end function.
 */
static void update_file_sizes(struct inode *inode, loff_t pos, unsigned copied)
{
	/* What matters to us is i_disksize. We don't write i_size anywhere */
	if (pos + copied > inode->i_size)
		i_size_write(inode, pos + copied);
	if (pos + copied > EXT3_I(inode)->i_disksize) {
		EXT3_I(inode)->i_disksize = pos + copied;
		mark_inode_dirty(inode);
	}
}

/*
 * We need to pick up the new inode size which generic_commit_write gave us
 * `file' can be NULL - eg, when called from page_symlink().
 *
 * ext3 never places buffers on inode->i_mapping->private_list.  metadata
 * buffers are managed internally.
 */
static int ext3_ordered_write_end(struct file *file,
				struct address_space *mapping,
				loff_t pos, unsigned len, unsigned copied,
				struct page *page, void *fsdata)
{
	handle_t *handle = ext3_journal_current_handle();
	struct inode *inode = file->f_mapping->host;
	unsigned from, to;
	int ret = 0, ret2;

	trace_ext3_ordered_write_end(inode, pos, len, copied);
	copied = block_write_end(file, mapping, pos, len, copied, page, fsdata);

	from = pos & (PAGE_CACHE_SIZE - 1);
	to = from + copied;
	ret = walk_page_buffers(handle, page_buffers(page),
		from, to, NULL, journal_dirty_data_fn);

	if (ret == 0)
		update_file_sizes(inode, pos, copied);
	/*
	 * There may be allocated blocks outside of i_size because
	 * we failed to copy some data. Prepare for truncate.
	 */
	if (pos + len > inode->i_size && ext3_can_truncate(inode))
		ext3_orphan_add(handle, inode);
	ret2 = ext3_journal_stop(handle);
	if (!ret)
		ret = ret2;
	unlock_page(page);
	page_cache_release(page);

	if (pos + len > inode->i_size)
		ext3_truncate_failed_write(inode);
	return ret ? ret : copied;
}

static int ext3_writeback_write_end(struct file *file,
				struct address_space *mapping,
				loff_t pos, unsigned len, unsigned copied,
				struct page *page, void *fsdata)
{
	handle_t *handle = ext3_journal_current_handle();
	struct inode *inode = file->f_mapping->host;
	int ret;

	trace_ext3_writeback_write_end(inode, pos, len, copied);
	copied = block_write_end(file, mapping, pos, len, copied, page, fsdata);
	update_file_sizes(inode, pos, copied);
	/*
	 * There may be allocated blocks outside of i_size because
	 * we failed to copy some data. Prepare for truncate.
	 */
	if (pos + len > inode->i_size && ext3_can_truncate(inode))
		ext3_orphan_add(handle, inode);
	ret = ext3_journal_stop(handle);
	unlock_page(page);
	page_cache_release(page);

	if (pos + len > inode->i_size)
		ext3_truncate_failed_write(inode);
	return ret ? ret : copied;
}

static int ext3_journalled_write_end(struct file *file,
				struct address_space *mapping,
				loff_t pos, unsigned len, unsigned copied,
				struct page *page, void *fsdata)
{
	handle_t *handle = ext3_journal_current_handle();
	struct inode *inode = mapping->host;
	struct ext3_inode_info *ei = EXT3_I(inode);
	int ret = 0, ret2;
	int partial = 0;
	unsigned from, to;

	trace_ext3_journalled_write_end(inode, pos, len, copied);
	from = pos & (PAGE_CACHE_SIZE - 1);
	to = from + len;

	if (copied < len) {
		if (!PageUptodate(page))
			copied = 0;
		page_zero_new_buffers(page, from + copied, to);
		to = from + copied;
	}

	ret = walk_page_buffers(handle, page_buffers(page), from,
				to, &partial, write_end_fn);
	if (!partial)
		SetPageUptodate(page);

	if (pos + copied > inode->i_size)
		i_size_write(inode, pos + copied);
	/*
	 * There may be allocated blocks outside of i_size because
	 * we failed to copy some data. Prepare for truncate.
	 */
	if (pos + len > inode->i_size && ext3_can_truncate(inode))
		ext3_orphan_add(handle, inode);
	ext3_set_inode_state(inode, EXT3_STATE_JDATA);
	atomic_set(&ei->i_datasync_tid, handle->h_transaction->t_tid);
	if (inode->i_size > ei->i_disksize) {
		ei->i_disksize = inode->i_size;
		ret2 = ext3_mark_inode_dirty(handle, inode);
		if (!ret)
			ret = ret2;
	}

	ret2 = ext3_journal_stop(handle);
	if (!ret)
		ret = ret2;
	unlock_page(page);
	page_cache_release(page);

	if (pos + len > inode->i_size)
		ext3_truncate_failed_write(inode);
	return ret ? ret : copied;
}

/*
 * bmap() is special.  It gets used by applications such as lilo and by
 * the swapper to find the on-disk block of a specific piece of data.
 *
 * Naturally, this is dangerous if the block concerned is still in the
 * journal.  If somebody makes a swapfile on an ext3 data-journaling
 * filesystem and enables swap, then they may get a nasty shock when the
 * data getting swapped to that swapfile suddenly gets overwritten by
 * the original zero's written out previously to the journal and
 * awaiting writeback in the kernel's buffer cache.
 *
 * So, if we see any bmap calls here on a modified, data-journaled file,
 * take extra steps to flush any blocks which might be in the cache.
 */
static sector_t ext3_bmap(struct address_space *mapping, sector_t block)
{
	struct inode *inode = mapping->host;
	journal_t *journal;
	int err;

	if (ext3_test_inode_state(inode, EXT3_STATE_JDATA)) {
		/*
		 * This is a REALLY heavyweight approach, but the use of
		 * bmap on dirty files is expected to be extremely rare:
		 * only if we run lilo or swapon on a freshly made file
		 * do we expect this to happen.
		 *
		 * (bmap requires CAP_SYS_RAWIO so this does not
		 * represent an unprivileged user DOS attack --- we'd be
		 * in trouble if mortal users could trigger this path at
		 * will.)
		 *
		 * NB. EXT3_STATE_JDATA is not set on files other than
		 * regular files.  If somebody wants to bmap a directory
		 * or symlink and gets confused because the buffer
		 * hasn't yet been flushed to disk, they deserve
		 * everything they get.
		 */

		ext3_clear_inode_state(inode, EXT3_STATE_JDATA);
		journal = EXT3_JOURNAL(inode);
		journal_lock_updates(journal);
		err = journal_flush(journal);
		journal_unlock_updates(journal);

		if (err)
			return 0;
	}

	return generic_block_bmap(mapping,block,ext3_get_block);
}

static int bget_one(handle_t *handle, struct buffer_head *bh)
{
	get_bh(bh);
	return 0;
}

static int bput_one(handle_t *handle, struct buffer_head *bh)
{
	put_bh(bh);
	return 0;
}

static int buffer_unmapped(handle_t *handle, struct buffer_head *bh)
{
	return !buffer_mapped(bh);
}

/*
 * Note that whenever we need to map blocks we start a transaction even if
 * we're not journalling data.  This is to preserve ordering: any hole
 * instantiation within __block_write_full_page -> ext3_get_block() should be
 * journalled along with the data so we don't crash and then get metadata which
 * refers to old data.
 *
 * In all journalling modes block_write_full_page() will start the I/O.
 *
 * We don't honour synchronous mounts for writepage().  That would be
 * disastrous.  Any write() or metadata operation will sync the fs for
 * us.
 */
static int ext3_ordered_writepage(struct page *page,
				struct writeback_control *wbc)
{
	struct inode *inode = page->mapping->host;
	struct buffer_head *page_bufs;
	handle_t *handle = NULL;
	int ret = 0;
	int err;

	J_ASSERT(PageLocked(page));
	/*
	 * We don't want to warn for emergency remount. The condition is
	 * ordered to avoid dereferencing inode->i_sb in non-error case to
	 * avoid slow-downs.
	 */
	WARN_ON_ONCE(IS_RDONLY(inode) &&
		     !(EXT3_SB(inode->i_sb)->s_mount_state & EXT3_ERROR_FS));

	/*
	 * We give up here if we're reentered, because it might be for a
	 * different filesystem.
	 */
	if (ext3_journal_current_handle())
		goto out_fail;

	trace_ext3_ordered_writepage(page);
	if (!page_has_buffers(page)) {
		create_empty_buffers(page, inode->i_sb->s_blocksize,
				(1 << BH_Dirty)|(1 << BH_Uptodate));
		page_bufs = page_buffers(page);
	} else {
		page_bufs = page_buffers(page);
		if (!walk_page_buffers(NULL, page_bufs, 0, PAGE_CACHE_SIZE,
				       NULL, buffer_unmapped)) {
			/* Provide NULL get_block() to catch bugs if buffers
			 * weren't really mapped */
			return block_write_full_page(page, NULL, wbc);
		}
	}
	handle = ext3_journal_start(inode, ext3_writepage_trans_blocks(inode));

	if (IS_ERR(handle)) {
		ret = PTR_ERR(handle);
		goto out_fail;
	}

	walk_page_buffers(handle, page_bufs, 0,
			PAGE_CACHE_SIZE, NULL, bget_one);

	ret = block_write_full_page(page, ext3_get_block, wbc);

	/*
	 * The page can become unlocked at any point now, and
	 * truncate can then come in and change things.  So we
	 * can't touch *page from now on.  But *page_bufs is
	 * safe due to elevated refcount.
	 */

	/*
	 * And attach them to the current transaction.  But only if
	 * block_write_full_page() succeeded.  Otherwise they are unmapped,
	 * and generally junk.
	 */
	if (ret == 0)
		ret = walk_page_buffers(handle, page_bufs, 0, PAGE_CACHE_SIZE,
					NULL, journal_dirty_data_fn);
	walk_page_buffers(handle, page_bufs, 0,
			PAGE_CACHE_SIZE, NULL, bput_one);
	err = ext3_journal_stop(handle);
	if (!ret)
		ret = err;
	return ret;

out_fail:
	redirty_page_for_writepage(wbc, page);
	unlock_page(page);
	return ret;
}

static int ext3_writeback_writepage(struct page *page,
				struct writeback_control *wbc)
{
	struct inode *inode = page->mapping->host;
	handle_t *handle = NULL;
	int ret = 0;
	int err;

	J_ASSERT(PageLocked(page));
	/*
	 * We don't want to warn for emergency remount. The condition is
	 * ordered to avoid dereferencing inode->i_sb in non-error case to
	 * avoid slow-downs.
	 */
	WARN_ON_ONCE(IS_RDONLY(inode) &&
		     !(EXT3_SB(inode->i_sb)->s_mount_state & EXT3_ERROR_FS));

	if (ext3_journal_current_handle())
		goto out_fail;

	trace_ext3_writeback_writepage(page);
	if (page_has_buffers(page)) {
		if (!walk_page_buffers(NULL, page_buffers(page), 0,
				      PAGE_CACHE_SIZE, NULL, buffer_unmapped)) {
			/* Provide NULL get_block() to catch bugs if buffers
			 * weren't really mapped */
			return block_write_full_page(page, NULL, wbc);
		}
	}

	handle = ext3_journal_start(inode, ext3_writepage_trans_blocks(inode));
	if (IS_ERR(handle)) {
		ret = PTR_ERR(handle);
		goto out_fail;
	}

	ret = block_write_full_page(page, ext3_get_block, wbc);

	err = ext3_journal_stop(handle);
	if (!ret)
		ret = err;
	return ret;

out_fail:
	redirty_page_for_writepage(wbc, page);
	unlock_page(page);
	return ret;
}

static int ext3_journalled_writepage(struct page *page,
				struct writeback_control *wbc)
{
	struct inode *inode = page->mapping->host;
	handle_t *handle = NULL;
	int ret = 0;
	int err;

	J_ASSERT(PageLocked(page));
	/*
	 * We don't want to warn for emergency remount. The condition is
	 * ordered to avoid dereferencing inode->i_sb in non-error case to
	 * avoid slow-downs.
	 */
	WARN_ON_ONCE(IS_RDONLY(inode) &&
		     !(EXT3_SB(inode->i_sb)->s_mount_state & EXT3_ERROR_FS));

	trace_ext3_journalled_writepage(page);
	if (!page_has_buffers(page) || PageChecked(page)) {
		if (ext3_journal_current_handle())
			goto no_write;

		handle = ext3_journal_start(inode,
					    ext3_writepage_trans_blocks(inode));
		if (IS_ERR(handle)) {
			ret = PTR_ERR(handle);
			goto no_write;
		}
		/*
		 * It's mmapped pagecache.  Add buffers and journal it.  There
		 * doesn't seem much point in redirtying the page here.
		 */
		ClearPageChecked(page);
		ret = __block_write_begin(page, 0, PAGE_CACHE_SIZE,
					  ext3_get_block);
		if (ret != 0) {
			ext3_journal_stop(handle);
			goto out_unlock;
		}
		ret = walk_page_buffers(handle, page_buffers(page), 0,
			PAGE_CACHE_SIZE, NULL, do_journal_get_write_access);

		err = walk_page_buffers(handle, page_buffers(page), 0,
				PAGE_CACHE_SIZE, NULL, write_end_fn);
		if (ret == 0)
			ret = err;
		ext3_set_inode_state(inode, EXT3_STATE_JDATA);
		atomic_set(&EXT3_I(inode)->i_datasync_tid,
			   handle->h_transaction->t_tid);
		unlock_page(page);
		err = ext3_journal_stop(handle);
		if (!ret)
			ret = err;
	} else {
		/*
		 * It is a page full of checkpoint-mode buffers. Go and write
		 * them. They should have been already mapped when they went
		 * to the journal so provide NULL get_block function to catch
		 * errors.
		 */
		ret = block_write_full_page(page, NULL, wbc);
	}
out:
	return ret;

no_write:
	redirty_page_for_writepage(wbc, page);
out_unlock:
	unlock_page(page);
	goto out;
}

static int ext3_readpage(struct file *file, struct page *page)
{
	trace_ext3_readpage(page);
	return mpage_readpage(page, ext3_get_block);
}

static int
ext3_readpages(struct file *file, struct address_space *mapping,
		struct list_head *pages, unsigned nr_pages)
{
	return mpage_readpages(mapping, pages, nr_pages, ext3_get_block);
}

static void ext3_invalidatepage(struct page *page, unsigned int offset,
				unsigned int length)
{
	journal_t *journal = EXT3_JOURNAL(page->mapping->host);

	trace_ext3_invalidatepage(page, offset, length);

	/*
	 * If it's a full truncate we just forget about the pending dirtying
	 */
	if (offset == 0 && length == PAGE_CACHE_SIZE)
		ClearPageChecked(page);

	journal_invalidatepage(journal, page, offset, length);
}

static int ext3_releasepage(struct page *page, gfp_t wait)
{
	journal_t *journal = EXT3_JOURNAL(page->mapping->host);

	trace_ext3_releasepage(page);
	WARN_ON(PageChecked(page));
	if (!page_has_buffers(page))
		return 0;
	return journal_try_to_free_buffers(journal, page, wait);
}

/*
 * If the O_DIRECT write will extend the file then add this inode to the
 * orphan list.  So recovery will truncate it back to the original size
 * if the machine crashes during the write.
 *
 * If the O_DIRECT write is intantiating holes inside i_size and the machine
 * crashes then stale disk data _may_ be exposed inside the file. But current
 * VFS code falls back into buffered path in that case so we are safe.
 */
static ssize_t ext3_direct_IO(struct kiocb *iocb, struct iov_iter *iter,
			      loff_t offset)
{
	struct file *file = iocb->ki_filp;
	struct inode *inode = file->f_mapping->host;
	struct ext3_inode_info *ei = EXT3_I(inode);
	handle_t *handle;
	ssize_t ret;
	int orphan = 0;
	size_t count = iov_iter_count(iter);
	int retries = 0;

	trace_ext3_direct_IO_enter(inode, offset, count, iov_iter_rw(iter));

	if (iov_iter_rw(iter) == WRITE) {
		loff_t final_size = offset + count;

		if (final_size > inode->i_size) {
			/* Credits for sb + inode write */
			handle = ext3_journal_start(inode, 2);
			if (IS_ERR(handle)) {
				ret = PTR_ERR(handle);
				goto out;
			}
			ret = ext3_orphan_add(handle, inode);
			if (ret) {
				ext3_journal_stop(handle);
				goto out;
			}
			orphan = 1;
			ei->i_disksize = inode->i_size;
			ext3_journal_stop(handle);
		}
	}

retry:
	ret = blockdev_direct_IO(iocb, inode, iter, offset, ext3_get_block);
	/*
	 * In case of error extending write may have instantiated a few
	 * blocks outside i_size. Trim these off again.
	 */
	if (unlikely(iov_iter_rw(iter) == WRITE && ret < 0)) {
		loff_t isize = i_size_read(inode);
		loff_t end = offset + count;

		if (end > isize)
			ext3_truncate_failed_direct_write(inode);
	}
	if (ret == -ENOSPC && ext3_should_retry_alloc(inode->i_sb, &retries))
		goto retry;

	if (orphan) {
		int err;

		/* Credits for sb + inode write */
		handle = ext3_journal_start(inode, 2);
		if (IS_ERR(handle)) {
			/* This is really bad luck. We've written the data
			 * but cannot extend i_size. Truncate allocated blocks
			 * and pretend the write failed... */
			ext3_truncate_failed_direct_write(inode);
			ret = PTR_ERR(handle);
			if (inode->i_nlink)
				ext3_orphan_del(NULL, inode);
			goto out;
		}
		if (inode->i_nlink)
			ext3_orphan_del(handle, inode);
		if (ret > 0) {
			loff_t end = offset + ret;
			if (end > inode->i_size) {
				ei->i_disksize = end;
				i_size_write(inode, end);
				/*
				 * We're going to return a positive `ret'
				 * here due to non-zero-length I/O, so there's
				 * no way of reporting error returns from
				 * ext3_mark_inode_dirty() to userspace.  So
				 * ignore it.
				 */
				ext3_mark_inode_dirty(handle, inode);
			}
		}
		err = ext3_journal_stop(handle);
		if (ret == 0)
			ret = err;
	}
out:
	trace_ext3_direct_IO_exit(inode, offset, count, iov_iter_rw(iter), ret);
	return ret;
}

/*
 * Pages can be marked dirty completely asynchronously from ext3's journalling
 * activity.  By filemap_sync_pte(), try_to_unmap_one(), etc.  We cannot do
 * much here because ->set_page_dirty is called under VFS locks.  The page is
 * not necessarily locked.
 *
 * We cannot just dirty the page and leave attached buffers clean, because the
 * buffers' dirty state is "definitive".  We cannot just set the buffers dirty
 * or jbddirty because all the journalling code will explode.
 *
 * So what we do is to mark the page "pending dirty" and next time writepage
 * is called, propagate that into the buffers appropriately.
 */
static int ext3_journalled_set_page_dirty(struct page *page)
{
	SetPageChecked(page);
	return __set_page_dirty_nobuffers(page);
}

static const struct address_space_operations ext3_ordered_aops = {
	.readpage		= ext3_readpage,
	.readpages		= ext3_readpages,
	.writepage		= ext3_ordered_writepage,
	.write_begin		= ext3_write_begin,
	.write_end		= ext3_ordered_write_end,
	.bmap			= ext3_bmap,
	.invalidatepage		= ext3_invalidatepage,
	.releasepage		= ext3_releasepage,
	.direct_IO		= ext3_direct_IO,
	.migratepage		= buffer_migrate_page,
	.is_partially_uptodate  = block_is_partially_uptodate,
	.is_dirty_writeback	= buffer_check_dirty_writeback,
	.error_remove_page	= generic_error_remove_page,
};

static const struct address_space_operations ext3_writeback_aops = {
	.readpage		= ext3_readpage,
	.readpages		= ext3_readpages,
	.writepage		= ext3_writeback_writepage,
	.write_begin		= ext3_write_begin,
	.write_end		= ext3_writeback_write_end,
	.bmap			= ext3_bmap,
	.invalidatepage		= ext3_invalidatepage,
	.releasepage		= ext3_releasepage,
	.direct_IO		= ext3_direct_IO,
	.migratepage		= buffer_migrate_page,
	.is_partially_uptodate  = block_is_partially_uptodate,
	.error_remove_page	= generic_error_remove_page,
};

static const struct address_space_operations ext3_journalled_aops = {
	.readpage		= ext3_readpage,
	.readpages		= ext3_readpages,
	.writepage		= ext3_journalled_writepage,
	.write_begin		= ext3_write_begin,
	.write_end		= ext3_journalled_write_end,
	.set_page_dirty		= ext3_journalled_set_page_dirty,
	.bmap			= ext3_bmap,
	.invalidatepage		= ext3_invalidatepage,
	.releasepage		= ext3_releasepage,
	.is_partially_uptodate  = block_is_partially_uptodate,
	.error_remove_page	= generic_error_remove_page,
};

void ext3_set_aops(struct inode *inode)
{
	if (ext3_should_order_data(inode))
		inode->i_mapping->a_ops = &ext3_ordered_aops;
	else if (ext3_should_writeback_data(inode))
		inode->i_mapping->a_ops = &ext3_writeback_aops;
	else
		inode->i_mapping->a_ops = &ext3_journalled_aops;
}

/*
 * ext3_block_truncate_page() zeroes out a mapping from file offset `from'
 * up to the end of the block which corresponds to `from'.
 * This required during truncate. We need to physically zero the tail end
 * of that block so it doesn't yield old data if the file is later grown.
 */
static int ext3_block_truncate_page(struct inode *inode, loff_t from)
{
	ext3_fsblk_t index = from >> PAGE_CACHE_SHIFT;
	unsigned offset = from & (PAGE_CACHE_SIZE - 1);
	unsigned blocksize, iblock, length, pos;
	struct page *page;
	handle_t *handle = NULL;
	struct buffer_head *bh;
	int err = 0;

	/* Truncated on block boundary - nothing to do */
	blocksize = inode->i_sb->s_blocksize;
	if ((from & (blocksize - 1)) == 0)
		return 0;

	page = grab_cache_page(inode->i_mapping, index);
	if (!page)
		return -ENOMEM;
	length = blocksize - (offset & (blocksize - 1));
	iblock = index << (PAGE_CACHE_SHIFT - inode->i_sb->s_blocksize_bits);

	if (!page_has_buffers(page))
		create_empty_buffers(page, blocksize, 0);

	/* Find the buffer that contains "offset" */
	bh = page_buffers(page);
	pos = blocksize;
	while (offset >= pos) {
		bh = bh->b_this_page;
		iblock++;
		pos += blocksize;
	}

	err = 0;
	if (buffer_freed(bh)) {
		BUFFER_TRACE(bh, "freed: skip");
		goto unlock;
	}

	if (!buffer_mapped(bh)) {
		BUFFER_TRACE(bh, "unmapped");
		ext3_get_block(inode, iblock, bh, 0);
		/* unmapped? It's a hole - nothing to do */
		if (!buffer_mapped(bh)) {
			BUFFER_TRACE(bh, "still unmapped");
			goto unlock;
		}
	}

	/* Ok, it's mapped. Make sure it's up-to-date */
	if (PageUptodate(page))
		set_buffer_uptodate(bh);

	if (!bh_uptodate_or_lock(bh)) {
		err = bh_submit_read(bh);
		/* Uhhuh. Read error. Complain and punt. */
		if (err)
			goto unlock;
	}

	/* data=writeback mode doesn't need transaction to zero-out data */
	if (!ext3_should_writeback_data(inode)) {
		/* We journal at most one block */
		handle = ext3_journal_start(inode, 1);
		if (IS_ERR(handle)) {
			clear_highpage(page);
			flush_dcache_page(page);
			err = PTR_ERR(handle);
			goto unlock;
		}
	}

	if (ext3_should_journal_data(inode)) {
		BUFFER_TRACE(bh, "get write access");
		err = ext3_journal_get_write_access(handle, bh);
		if (err)
			goto stop;
	}

	zero_user(page, offset, length);
	BUFFER_TRACE(bh, "zeroed end of block");

	err = 0;
	if (ext3_should_journal_data(inode)) {
		err = ext3_journal_dirty_metadata(handle, bh);
	} else {
		if (ext3_should_order_data(inode))
			err = ext3_journal_dirty_data(handle, bh);
		mark_buffer_dirty(bh);
	}
stop:
	if (handle)
		ext3_journal_stop(handle);

unlock:
	unlock_page(page);
	page_cache_release(page);
	return err;
}

/*
 * Probably it should be a library function... search for first non-zero word
 * or memcmp with zero_page, whatever is better for particular architecture.
 * Linus?
 */
static inline int all_zeroes(__le32 *p, __le32 *q)
{
	while (p < q)
		if (*p++)
			return 0;
	return 1;
}

/**
 *	ext3_find_shared - find the indirect blocks for partial truncation.
 *	@inode:	  inode in question
 *	@depth:	  depth of the affected branch
 *	@offsets: offsets of pointers in that branch (see ext3_block_to_path)
 *	@chain:	  place to store the pointers to partial indirect blocks
 *	@top:	  place to the (detached) top of branch
 *
 *	This is a helper function used by ext3_truncate().
 *
 *	When we do truncate() we may have to clean the ends of several
 *	indirect blocks but leave the blocks themselves alive. Block is
 *	partially truncated if some data below the new i_size is referred
 *	from it (and it is on the path to the first completely truncated
 *	data block, indeed).  We have to free the top of that path along
 *	with everything to the right of the path. Since no allocation
 *	past the truncation point is possible until ext3_truncate()
 *	finishes, we may safely do the latter, but top of branch may
 *	require special attention - pageout below the truncation point
 *	might try to populate it.
 *
 *	We atomically detach the top of branch from the tree, store the
 *	block number of its root in *@top, pointers to buffer_heads of
 *	partially truncated blocks - in @chain[].bh and pointers to
 *	their last elements that should not be removed - in
 *	@chain[].p. Return value is the pointer to last filled element
 *	of @chain.
 *
 *	The work left to caller to do the actual freeing of subtrees:
 *		a) free the subtree starting from *@top
 *		b) free the subtrees whose roots are stored in
 *			(@chain[i].p+1 .. end of @chain[i].bh->b_data)
 *		c) free the subtrees growing from the inode past the @chain[0].
 *			(no partially truncated stuff there).  */

static Indirect *ext3_find_shared(struct inode *inode, int depth,
			int offsets[4], Indirect chain[4], __le32 *top)
{
	Indirect *partial, *p;
	int k, err;

	*top = 0;
	/* Make k index the deepest non-null offset + 1 */
	for (k = depth; k > 1 && !offsets[k-1]; k--)
		;
	partial = ext3_get_branch(inode, k, offsets, chain, &err);
	/* Writer: pointers */
	if (!partial)
		partial = chain + k-1;
	/*
	 * If the branch acquired continuation since we've looked at it -
	 * fine, it should all survive and (new) top doesn't belong to us.
	 */
	if (!partial->key && *partial->p)
		/* Writer: end */
		goto no_top;
	for (p=partial; p>chain && all_zeroes((__le32*)p->bh->b_data,p->p); p--)
		;
	/*
	 * OK, we've found the last block that must survive. The rest of our
	 * branch should be detached before unlocking. However, if that rest
	 * of branch is all ours and does not grow immediately from the inode
	 * it's easier to cheat and just decrement partial->p.
	 */
	if (p == chain + k - 1 && p > chain) {
		p->p--;
	} else {
		*top = *p->p;
		/* Nope, don't do this in ext3.  Must leave the tree intact */
#if 0
		*p->p = 0;
#endif
	}
	/* Writer: end */

	while(partial > p) {
		brelse(partial->bh);
		partial--;
	}
no_top:
	return partial;
}

/*
 * Zero a number of block pointers in either an inode or an indirect block.
 * If we restart the transaction we must again get write access to the
 * indirect block for further modification.
 *
 * We release `count' blocks on disk, but (last - first) may be greater
 * than `count' because there can be holes in there.
 */
static void ext3_clear_blocks(handle_t *handle, struct inode *inode,
		struct buffer_head *bh, ext3_fsblk_t block_to_free,
		unsigned long count, __le32 *first, __le32 *last)
{
	__le32 *p;
	if (try_to_extend_transaction(handle, inode)) {
		if (bh) {
			BUFFER_TRACE(bh, "call ext3_journal_dirty_metadata");
			if (ext3_journal_dirty_metadata(handle, bh))
				return;
		}
		ext3_mark_inode_dirty(handle, inode);
		truncate_restart_transaction(handle, inode);
		if (bh) {
			BUFFER_TRACE(bh, "retaking write access");
			if (ext3_journal_get_write_access(handle, bh))
				return;
		}
	}

	/*
	 * Any buffers which are on the journal will be in memory. We find
	 * them on the hash table so journal_revoke() will run journal_forget()
	 * on them.  We've already detached each block from the file, so
	 * bforget() in journal_forget() should be safe.
	 *
	 * AKPM: turn on bforget in journal_forget()!!!
	 */
	for (p = first; p < last; p++) {
		u32 nr = le32_to_cpu(*p);
		if (nr) {
			struct buffer_head *bh;

			*p = 0;
			bh = sb_find_get_block(inode->i_sb, nr);
			ext3_forget(handle, 0, inode, bh, nr);
		}
	}

	ext3_free_blocks(handle, inode, block_to_free, count);
}

/**
 * ext3_free_data - free a list of data blocks
 * @handle:	handle for this transaction
 * @inode:	inode we are dealing with
 * @this_bh:	indirect buffer_head which contains *@first and *@last
 * @first:	array of block numbers
 * @last:	points immediately past the end of array
 *
 * We are freeing all blocks referred from that array (numbers are stored as
 * little-endian 32-bit) and updating @inode->i_blocks appropriately.
 *
 * We accumulate contiguous runs of blocks to free.  Conveniently, if these
 * blocks are contiguous then releasing them at one time will only affect one
 * or two bitmap blocks (+ group descriptor(s) and superblock) and we won't
 * actually use a lot of journal space.
 *
 * @this_bh will be %NULL if @first and @last point into the inode's direct
 * block pointers.
 */
static void ext3_free_data(handle_t *handle, struct inode *inode,
			   struct buffer_head *this_bh,
			   __le32 *first, __le32 *last)
{
	ext3_fsblk_t block_to_free = 0;    /* Starting block # of a run */
	unsigned long count = 0;	    /* Number of blocks in the run */
	__le32 *block_to_free_p = NULL;	    /* Pointer into inode/ind
					       corresponding to
					       block_to_free */
	ext3_fsblk_t nr;		    /* Current block # */
	__le32 *p;			    /* Pointer into inode/ind
					       for current block */
	int err;

	if (this_bh) {				/* For indirect block */
		BUFFER_TRACE(this_bh, "get_write_access");
		err = ext3_journal_get_write_access(handle, this_bh);
		/* Important: if we can't update the indirect pointers
		 * to the blocks, we can't free them. */
		if (err)
			return;
	}

	for (p = first; p < last; p++) {
		nr = le32_to_cpu(*p);
		if (nr) {
			/* accumulate blocks to free if they're contiguous */
			if (count == 0) {
				block_to_free = nr;
				block_to_free_p = p;
				count = 1;
			} else if (nr == block_to_free + count) {
				count++;
			} else {
				ext3_clear_blocks(handle, inode, this_bh,
						  block_to_free,
						  count, block_to_free_p, p);
				block_to_free = nr;
				block_to_free_p = p;
				count = 1;
			}
		}
	}

	if (count > 0)
		ext3_clear_blocks(handle, inode, this_bh, block_to_free,
				  count, block_to_free_p, p);

	if (this_bh) {
		BUFFER_TRACE(this_bh, "call ext3_journal_dirty_metadata");

		/*
		 * The buffer head should have an attached journal head at this
		 * point. However, if the data is corrupted and an indirect
		 * block pointed to itself, it would have been detached when
		 * the block was cleared. Check for this instead of OOPSing.
		 */
		if (bh2jh(this_bh))
			ext3_journal_dirty_metadata(handle, this_bh);
		else
			ext3_error(inode->i_sb, "ext3_free_data",
				   "circular indirect block detected, "
				   "inode=%lu, block=%llu",
				   inode->i_ino,
				   (unsigned long long)this_bh->b_blocknr);
	}
}

/**
 *	ext3_free_branches - free an array of branches
 *	@handle: JBD handle for this transaction
 *	@inode:	inode we are dealing with
 *	@parent_bh: the buffer_head which contains *@first and *@last
 *	@first:	array of block numbers
 *	@last:	pointer immediately past the end of array
 *	@depth:	depth of the branches to free
 *
 *	We are freeing all blocks referred from these branches (numbers are
 *	stored as little-endian 32-bit) and updating @inode->i_blocks
 *	appropriately.
 */
static void ext3_free_branches(handle_t *handle, struct inode *inode,
			       struct buffer_head *parent_bh,
			       __le32 *first, __le32 *last, int depth)
{
	ext3_fsblk_t nr;
	__le32 *p;

	if (is_handle_aborted(handle))
		return;

	if (depth--) {
		struct buffer_head *bh;
		int addr_per_block = EXT3_ADDR_PER_BLOCK(inode->i_sb);
		p = last;
		while (--p >= first) {
			nr = le32_to_cpu(*p);
			if (!nr)
				continue;		/* A hole */

			/* Go read the buffer for the next level down */
			bh = sb_bread(inode->i_sb, nr);

			/*
			 * A read failure? Report error and clear slot
			 * (should be rare).
			 */
			if (!bh) {
				ext3_error(inode->i_sb, "ext3_free_branches",
					   "Read failure, inode=%lu, block="E3FSBLK,
					   inode->i_ino, nr);
				continue;
			}

			/* This zaps the entire block.  Bottom up. */
			BUFFER_TRACE(bh, "free child branches");
			ext3_free_branches(handle, inode, bh,
					   (__le32*)bh->b_data,
					   (__le32*)bh->b_data + addr_per_block,
					   depth);

			/*
			 * Everything below this this pointer has been
			 * released.  Now let this top-of-subtree go.
			 *
			 * We want the freeing of this indirect block to be
			 * atomic in the journal with the updating of the
			 * bitmap block which owns it.  So make some room in
			 * the journal.
			 *
			 * We zero the parent pointer *after* freeing its
			 * pointee in the bitmaps, so if extend_transaction()
			 * for some reason fails to put the bitmap changes and
			 * the release into the same transaction, recovery
			 * will merely complain about releasing a free block,
			 * rather than leaking blocks.
			 */
			if (is_handle_aborted(handle))
				return;
			if (try_to_extend_transaction(handle, inode)) {
				ext3_mark_inode_dirty(handle, inode);
				truncate_restart_transaction(handle, inode);
			}

			/*
			 * We've probably journalled the indirect block several
			 * times during the truncate.  But it's no longer
			 * needed and we now drop it from the transaction via
			 * journal_revoke().
			 *
			 * That's easy if it's exclusively part of this
			 * transaction.  But if it's part of the committing
			 * transaction then journal_forget() will simply
			 * brelse() it.  That means that if the underlying
			 * block is reallocated in ext3_get_block(),
			 * unmap_underlying_metadata() will find this block
			 * and will try to get rid of it.  damn, damn. Thus
			 * we don't allow a block to be reallocated until
			 * a transaction freeing it has fully committed.
			 *
			 * We also have to make sure journal replay after a
			 * crash does not overwrite non-journaled data blocks
			 * with old metadata when the block got reallocated for
			 * data.  Thus we have to store a revoke record for a
			 * block in the same transaction in which we free the
			 * block.
			 */
			ext3_forget(handle, 1, inode, bh, bh->b_blocknr);

			ext3_free_blocks(handle, inode, nr, 1);

			if (parent_bh) {
				/*
				 * The block which we have just freed is
				 * pointed to by an indirect block: journal it
				 */
				BUFFER_TRACE(parent_bh, "get_write_access");
				if (!ext3_journal_get_write_access(handle,
								   parent_bh)){
					*p = 0;
					BUFFER_TRACE(parent_bh,
					"call ext3_journal_dirty_metadata");
					ext3_journal_dirty_metadata(handle,
								    parent_bh);
				}
			}
		}
	} else {
		/* We have reached the bottom of the tree. */
		BUFFER_TRACE(parent_bh, "free data blocks");
		ext3_free_data(handle, inode, parent_bh, first, last);
	}
}

int ext3_can_truncate(struct inode *inode)
{
	if (S_ISREG(inode->i_mode))
		return 1;
	if (S_ISDIR(inode->i_mode))
		return 1;
	if (S_ISLNK(inode->i_mode))
		return !ext3_inode_is_fast_symlink(inode);
	return 0;
}

/*
 * ext3_truncate()
 *
 * We block out ext3_get_block() block instantiations across the entire
 * transaction, and VFS/VM ensures that ext3_truncate() cannot run
 * simultaneously on behalf of the same inode.
 *
 * As we work through the truncate and commit bits of it to the journal there
 * is one core, guiding principle: the file's tree must always be consistent on
 * disk.  We must be able to restart the truncate after a crash.
 *
 * The file's tree may be transiently inconsistent in memory (although it
 * probably isn't), but whenever we close off and commit a journal transaction,
 * the contents of (the filesystem + the journal) must be consistent and
 * restartable.  It's pretty simple, really: bottom up, right to left (although
 * left-to-right works OK too).
 *
 * Note that at recovery time, journal replay occurs *before* the restart of
 * truncate against the orphan inode list.
 *
 * The committed inode has the new, desired i_size (which is the same as
 * i_disksize in this case).  After a crash, ext3_orphan_cleanup() will see
 * that this inode's truncate did not complete and it will again call
 * ext3_truncate() to have another go.  So there will be instantiated blocks
 * to the right of the truncation point in a crashed ext3 filesystem.  But
 * that's fine - as long as they are linked from the inode, the post-crash
 * ext3_truncate() run will find them and release them.
 */
void ext3_truncate(struct inode *inode)
{
	handle_t *handle;
	struct ext3_inode_info *ei = EXT3_I(inode);
	__le32 *i_data = ei->i_data;
	int addr_per_block = EXT3_ADDR_PER_BLOCK(inode->i_sb);
	int offsets[4];
	Indirect chain[4];
	Indirect *partial;
	__le32 nr = 0;
	int n;
	long last_block;
	unsigned blocksize = inode->i_sb->s_blocksize;

	trace_ext3_truncate_enter(inode);

	if (!ext3_can_truncate(inode))
		goto out_notrans;

	if (inode->i_size == 0 && ext3_should_writeback_data(inode))
		ext3_set_inode_state(inode, EXT3_STATE_FLUSH_ON_CLOSE);

	handle = start_transaction(inode);
	if (IS_ERR(handle))
		goto out_notrans;

	last_block = (inode->i_size + blocksize-1)
					>> EXT3_BLOCK_SIZE_BITS(inode->i_sb);
	n = ext3_block_to_path(inode, last_block, offsets, NULL);
	if (n == 0)
		goto out_stop;	/* error */

	/*
	 * OK.  This truncate is going to happen.  We add the inode to the
	 * orphan list, so that if this truncate spans multiple transactions,
	 * and we crash, we will resume the truncate when the filesystem
	 * recovers.  It also marks the inode dirty, to catch the new size.
	 *
	 * Implication: the file must always be in a sane, consistent
	 * truncatable state while each transaction commits.
	 */
	if (ext3_orphan_add(handle, inode))
		goto out_stop;

	/*
	 * The orphan list entry will now protect us from any crash which
	 * occurs before the truncate completes, so it is now safe to propagate
	 * the new, shorter inode size (held for now in i_size) into the
	 * on-disk inode. We do this via i_disksize, which is the value which
	 * ext3 *really* writes onto the disk inode.
	 */
	ei->i_disksize = inode->i_size;

	/*
	 * From here we block out all ext3_get_block() callers who want to
	 * modify the block allocation tree.
	 */
	mutex_lock(&ei->truncate_mutex);

	if (n == 1) {		/* direct blocks */
		ext3_free_data(handle, inode, NULL, i_data+offsets[0],
			       i_data + EXT3_NDIR_BLOCKS);
		goto do_indirects;
	}

	partial = ext3_find_shared(inode, n, offsets, chain, &nr);
	/* Kill the top of shared branch (not detached) */
	if (nr) {
		if (partial == chain) {
			/* Shared branch grows from the inode */
			ext3_free_branches(handle, inode, NULL,
					   &nr, &nr+1, (chain+n-1) - partial);
			*partial->p = 0;
			/*
			 * We mark the inode dirty prior to restart,
			 * and prior to stop.  No need for it here.
			 */
		} else {
			/* Shared branch grows from an indirect block */
			ext3_free_branches(handle, inode, partial->bh,
					partial->p,
					partial->p+1, (chain+n-1) - partial);
		}
	}
	/* Clear the ends of indirect blocks on the shared branch */
	while (partial > chain) {
		ext3_free_branches(handle, inode, partial->bh, partial->p + 1,
				   (__le32*)partial->bh->b_data+addr_per_block,
				   (chain+n-1) - partial);
		BUFFER_TRACE(partial->bh, "call brelse");
		brelse (partial->bh);
		partial--;
	}
do_indirects:
	/* Kill the remaining (whole) subtrees */
	switch (offsets[0]) {
	default:
		nr = i_data[EXT3_IND_BLOCK];
		if (nr) {
			ext3_free_branches(handle, inode, NULL, &nr, &nr+1, 1);
			i_data[EXT3_IND_BLOCK] = 0;
		}
	case EXT3_IND_BLOCK:
		nr = i_data[EXT3_DIND_BLOCK];
		if (nr) {
			ext3_free_branches(handle, inode, NULL, &nr, &nr+1, 2);
			i_data[EXT3_DIND_BLOCK] = 0;
		}
	case EXT3_DIND_BLOCK:
		nr = i_data[EXT3_TIND_BLOCK];
		if (nr) {
			ext3_free_branches(handle, inode, NULL, &nr, &nr+1, 3);
			i_data[EXT3_TIND_BLOCK] = 0;
		}
	case EXT3_TIND_BLOCK:
		;
	}

	ext3_discard_reservation(inode);

	mutex_unlock(&ei->truncate_mutex);
	inode->i_mtime = inode->i_ctime = CURRENT_TIME_SEC;
	ext3_mark_inode_dirty(handle, inode);

	/*
	 * In a multi-transaction truncate, we only make the final transaction
	 * synchronous
	 */
	if (IS_SYNC(inode))
		handle->h_sync = 1;
out_stop:
	/*
	 * If this was a simple ftruncate(), and the file will remain alive
	 * then we need to clear up the orphan record which we created above.
	 * However, if this was a real unlink then we were called by
	 * ext3_evict_inode(), and we allow that function to clean up the
	 * orphan info for us.
	 */
	if (inode->i_nlink)
		ext3_orphan_del(handle, inode);

	ext3_journal_stop(handle);
	trace_ext3_truncate_exit(inode);
	return;
out_notrans:
	/*
	 * Delete the inode from orphan list so that it doesn't stay there
	 * forever and trigger assertion on umount.
	 */
	if (inode->i_nlink)
		ext3_orphan_del(NULL, inode);
	trace_ext3_truncate_exit(inode);
}

static ext3_fsblk_t ext3_get_inode_block(struct super_block *sb,
		unsigned long ino, struct ext3_iloc *iloc)
{
	unsigned long block_group;
	unsigned long offset;
	ext3_fsblk_t block;
	struct ext3_group_desc *gdp;

	if (!ext3_valid_inum(sb, ino)) {
		/*
		 * This error is already checked for in namei.c unless we are
		 * looking at an NFS filehandle, in which case no error
		 * report is needed
		 */
		return 0;
	}

	block_group = (ino - 1) / EXT3_INODES_PER_GROUP(sb);
	gdp = ext3_get_group_desc(sb, block_group, NULL);
	if (!gdp)
		return 0;
	/*
	 * Figure out the offset within the block group inode table
	 */
	offset = ((ino - 1) % EXT3_INODES_PER_GROUP(sb)) *
		EXT3_INODE_SIZE(sb);
	block = le32_to_cpu(gdp->bg_inode_table) +
		(offset >> EXT3_BLOCK_SIZE_BITS(sb));

	iloc->block_group = block_group;
	iloc->offset = offset & (EXT3_BLOCK_SIZE(sb) - 1);
	return block;
}

/*
 * ext3_get_inode_loc returns with an extra refcount against the inode's
 * underlying buffer_head on success. If 'in_mem' is true, we have all
 * data in memory that is needed to recreate the on-disk version of this
 * inode.
 */
static int __ext3_get_inode_loc(struct inode *inode,
				struct ext3_iloc *iloc, int in_mem)
{
	ext3_fsblk_t block;
	struct buffer_head *bh;

	block = ext3_get_inode_block(inode->i_sb, inode->i_ino, iloc);
	if (!block)
		return -EIO;

	bh = sb_getblk(inode->i_sb, block);
	if (unlikely(!bh)) {
		ext3_error (inode->i_sb, "ext3_get_inode_loc",
				"unable to read inode block - "
				"inode=%lu, block="E3FSBLK,
				 inode->i_ino, block);
		return -ENOMEM;
	}
	if (!buffer_uptodate(bh)) {
		lock_buffer(bh);

		/*
		 * If the buffer has the write error flag, we have failed
		 * to write out another inode in the same block.  In this
		 * case, we don't have to read the block because we may
		 * read the old inode data successfully.
		 */
		if (buffer_write_io_error(bh) && !buffer_uptodate(bh))
			set_buffer_uptodate(bh);

		if (buffer_uptodate(bh)) {
			/* someone brought it uptodate while we waited */
			unlock_buffer(bh);
			goto has_buffer;
		}

		/*
		 * If we have all information of the inode in memory and this
		 * is the only valid inode in the block, we need not read the
		 * block.
		 */
		if (in_mem) {
			struct buffer_head *bitmap_bh;
			struct ext3_group_desc *desc;
			int inodes_per_buffer;
			int inode_offset, i;
			int block_group;
			int start;

			block_group = (inode->i_ino - 1) /
					EXT3_INODES_PER_GROUP(inode->i_sb);
			inodes_per_buffer = bh->b_size /
				EXT3_INODE_SIZE(inode->i_sb);
			inode_offset = ((inode->i_ino - 1) %
					EXT3_INODES_PER_GROUP(inode->i_sb));
			start = inode_offset & ~(inodes_per_buffer - 1);

			/* Is the inode bitmap in cache? */
			desc = ext3_get_group_desc(inode->i_sb,
						block_group, NULL);
			if (!desc)
				goto make_io;

			bitmap_bh = sb_getblk(inode->i_sb,
					le32_to_cpu(desc->bg_inode_bitmap));
			if (unlikely(!bitmap_bh))
				goto make_io;

			/*
			 * If the inode bitmap isn't in cache then the
			 * optimisation may end up performing two reads instead
			 * of one, so skip it.
			 */
			if (!buffer_uptodate(bitmap_bh)) {
				brelse(bitmap_bh);
				goto make_io;
			}
			for (i = start; i < start + inodes_per_buffer; i++) {
				if (i == inode_offset)
					continue;
				if (ext3_test_bit(i, bitmap_bh->b_data))
					break;
			}
			brelse(bitmap_bh);
			if (i == start + inodes_per_buffer) {
				/* all other inodes are free, so skip I/O */
				memset(bh->b_data, 0, bh->b_size);
				set_buffer_uptodate(bh);
				unlock_buffer(bh);
				goto has_buffer;
			}
		}

make_io:
		/*
		 * There are other valid inodes in the buffer, this inode
		 * has in-inode xattrs, or we don't have this inode in memory.
		 * Read the block from disk.
		 */
		trace_ext3_load_inode(inode);
		get_bh(bh);
		bh->b_end_io = end_buffer_read_sync;
		submit_bh(READ | REQ_META | REQ_PRIO, bh);
		wait_on_buffer(bh);
		if (!buffer_uptodate(bh)) {
			ext3_error(inode->i_sb, "ext3_get_inode_loc",
					"unable to read inode block - "
					"inode=%lu, block="E3FSBLK,
					inode->i_ino, block);
			brelse(bh);
			return -EIO;
		}
	}
has_buffer:
	iloc->bh = bh;
	return 0;
}

int ext3_get_inode_loc(struct inode *inode, struct ext3_iloc *iloc)
{
	/* We have all inode data except xattrs in memory here. */
	return __ext3_get_inode_loc(inode, iloc,
		!ext3_test_inode_state(inode, EXT3_STATE_XATTR));
}

void ext3_set_inode_flags(struct inode *inode)
{
	unsigned int flags = EXT3_I(inode)->i_flags;

	inode->i_flags &= ~(S_SYNC|S_APPEND|S_IMMUTABLE|S_NOATIME|S_DIRSYNC);
	if (flags & EXT3_SYNC_FL)
		inode->i_flags |= S_SYNC;
	if (flags & EXT3_APPEND_FL)
		inode->i_flags |= S_APPEND;
	if (flags & EXT3_IMMUTABLE_FL)
		inode->i_flags |= S_IMMUTABLE;
	if (flags & EXT3_NOATIME_FL)
		inode->i_flags |= S_NOATIME;
	if (flags & EXT3_DIRSYNC_FL)
		inode->i_flags |= S_DIRSYNC;
}

/* Propagate flags from i_flags to EXT3_I(inode)->i_flags */
void ext3_get_inode_flags(struct ext3_inode_info *ei)
{
	unsigned int flags = ei->vfs_inode.i_flags;

	ei->i_flags &= ~(EXT3_SYNC_FL|EXT3_APPEND_FL|
			EXT3_IMMUTABLE_FL|EXT3_NOATIME_FL|EXT3_DIRSYNC_FL);
	if (flags & S_SYNC)
		ei->i_flags |= EXT3_SYNC_FL;
	if (flags & S_APPEND)
		ei->i_flags |= EXT3_APPEND_FL;
	if (flags & S_IMMUTABLE)
		ei->i_flags |= EXT3_IMMUTABLE_FL;
	if (flags & S_NOATIME)
		ei->i_flags |= EXT3_NOATIME_FL;
	if (flags & S_DIRSYNC)
		ei->i_flags |= EXT3_DIRSYNC_FL;
}

struct inode *ext3_iget(struct super_block *sb, unsigned long ino)
{
	struct ext3_iloc iloc;
	struct ext3_inode *raw_inode;
	struct ext3_inode_info *ei;
	struct buffer_head *bh;
	struct inode *inode;
	journal_t *journal = EXT3_SB(sb)->s_journal;
	transaction_t *transaction;
	long ret;
	int block;
	uid_t i_uid;
	gid_t i_gid;

	inode = iget_locked(sb, ino);
	if (!inode)
		return ERR_PTR(-ENOMEM);
	if (!(inode->i_state & I_NEW))
		return inode;

	ei = EXT3_I(inode);
	ei->i_block_alloc_info = NULL;

	ret = __ext3_get_inode_loc(inode, &iloc, 0);
	if (ret < 0)
		goto bad_inode;
	bh = iloc.bh;
	raw_inode = ext3_raw_inode(&iloc);
	inode->i_mode = le16_to_cpu(raw_inode->i_mode);
	i_uid = (uid_t)le16_to_cpu(raw_inode->i_uid_low);
	i_gid = (gid_t)le16_to_cpu(raw_inode->i_gid_low);
	if(!(test_opt (inode->i_sb, NO_UID32))) {
		i_uid |= le16_to_cpu(raw_inode->i_uid_high) << 16;
		i_gid |= le16_to_cpu(raw_inode->i_gid_high) << 16;
	}
	i_uid_write(inode, i_uid);
	i_gid_write(inode, i_gid);
	set_nlink(inode, le16_to_cpu(raw_inode->i_links_count));
	inode->i_size = le32_to_cpu(raw_inode->i_size);
	inode->i_atime.tv_sec = (signed)le32_to_cpu(raw_inode->i_atime);
	inode->i_ctime.tv_sec = (signed)le32_to_cpu(raw_inode->i_ctime);
	inode->i_mtime.tv_sec = (signed)le32_to_cpu(raw_inode->i_mtime);
	inode->i_atime.tv_nsec = inode->i_ctime.tv_nsec = inode->i_mtime.tv_nsec = 0;

	ei->i_state_flags = 0;
	ei->i_dir_start_lookup = 0;
	ei->i_dtime = le32_to_cpu(raw_inode->i_dtime);
	/* We now have enough fields to check if the inode was active or not.
	 * This is needed because nfsd might try to access dead inodes
	 * the test is that same one that e2fsck uses
	 * NeilBrown 1999oct15
	 */
	if (inode->i_nlink == 0) {
		if (inode->i_mode == 0 ||
		    !(EXT3_SB(inode->i_sb)->s_mount_state & EXT3_ORPHAN_FS)) {
			/* this inode is deleted */
			brelse (bh);
			ret = -ESTALE;
			goto bad_inode;
		}
		/* The only unlinked inodes we let through here have
		 * valid i_mode and are being read by the orphan
		 * recovery code: that's fine, we're about to complete
		 * the process of deleting those. */
	}
	inode->i_blocks = le32_to_cpu(raw_inode->i_blocks);
	ei->i_flags = le32_to_cpu(raw_inode->i_flags);
#ifdef EXT3_FRAGMENTS
	ei->i_faddr = le32_to_cpu(raw_inode->i_faddr);
	ei->i_frag_no = raw_inode->i_frag;
	ei->i_frag_size = raw_inode->i_fsize;
#endif
	ei->i_file_acl = le32_to_cpu(raw_inode->i_file_acl);
	if (!S_ISREG(inode->i_mode)) {
		ei->i_dir_acl = le32_to_cpu(raw_inode->i_dir_acl);
	} else {
		inode->i_size |=
			((__u64)le32_to_cpu(raw_inode->i_size_high)) << 32;
	}
	ei->i_disksize = inode->i_size;
	inode->i_generation = le32_to_cpu(raw_inode->i_generation);
	ei->i_block_group = iloc.block_group;
	/*
	 * NOTE! The in-memory inode i_data array is in little-endian order
	 * even on big-endian machines: we do NOT byteswap the block numbers!
	 */
	for (block = 0; block < EXT3_N_BLOCKS; block++)
		ei->i_data[block] = raw_inode->i_block[block];
	INIT_LIST_HEAD(&ei->i_orphan);

	/*
	 * Set transaction id's of transactions that have to be committed
	 * to finish f[data]sync. We set them to currently running transaction
	 * as we cannot be sure that the inode or some of its metadata isn't
	 * part of the transaction - the inode could have been reclaimed and
	 * now it is reread from disk.
	 */
	if (journal) {
		tid_t tid;

		spin_lock(&journal->j_state_lock);
		if (journal->j_running_transaction)
			transaction = journal->j_running_transaction;
		else
			transaction = journal->j_committing_transaction;
		if (transaction)
			tid = transaction->t_tid;
		else
			tid = journal->j_commit_sequence;
		spin_unlock(&journal->j_state_lock);
		atomic_set(&ei->i_sync_tid, tid);
		atomic_set(&ei->i_datasync_tid, tid);
	}

	if (inode->i_ino >= EXT3_FIRST_INO(inode->i_sb) + 1 &&
	    EXT3_INODE_SIZE(inode->i_sb) > EXT3_GOOD_OLD_INODE_SIZE) {
		/*
		 * When mke2fs creates big inodes it does not zero out
		 * the unused bytes above EXT3_GOOD_OLD_INODE_SIZE,
		 * so ignore those first few inodes.
		 */
		ei->i_extra_isize = le16_to_cpu(raw_inode->i_extra_isize);
		if (EXT3_GOOD_OLD_INODE_SIZE + ei->i_extra_isize >
		    EXT3_INODE_SIZE(inode->i_sb)) {
			brelse (bh);
			ret = -EIO;
			goto bad_inode;
		}
		if (ei->i_extra_isize == 0) {
			/* The extra space is currently unused. Use it. */
			ei->i_extra_isize = sizeof(struct ext3_inode) -
					    EXT3_GOOD_OLD_INODE_SIZE;
		} else {
			__le32 *magic = (void *)raw_inode +
					EXT3_GOOD_OLD_INODE_SIZE +
					ei->i_extra_isize;
			if (*magic == cpu_to_le32(EXT3_XATTR_MAGIC))
				 ext3_set_inode_state(inode, EXT3_STATE_XATTR);
		}
	} else
		ei->i_extra_isize = 0;

	if (S_ISREG(inode->i_mode)) {
		inode->i_op = &ext3_file_inode_operations;
		inode->i_fop = &ext3_file_operations;
		ext3_set_aops(inode);
	} else if (S_ISDIR(inode->i_mode)) {
		inode->i_op = &ext3_dir_inode_operations;
		inode->i_fop = &ext3_dir_operations;
	} else if (S_ISLNK(inode->i_mode)) {
		if (ext3_inode_is_fast_symlink(inode)) {
			inode->i_op = &ext3_fast_symlink_inode_operations;
			nd_terminate_link(ei->i_data, inode->i_size,
				sizeof(ei->i_data) - 1);
		} else {
			inode->i_op = &ext3_symlink_inode_operations;
			ext3_set_aops(inode);
		}
	} else {
		inode->i_op = &ext3_special_inode_operations;
		if (raw_inode->i_block[0])
			init_special_inode(inode, inode->i_mode,
			   old_decode_dev(le32_to_cpu(raw_inode->i_block[0])));
		else
			init_special_inode(inode, inode->i_mode,
			   new_decode_dev(le32_to_cpu(raw_inode->i_block[1])));
	}
	brelse (iloc.bh);
	ext3_set_inode_flags(inode);
	unlock_new_inode(inode);
	return inode;

bad_inode:
	iget_failed(inode);
	return ERR_PTR(ret);
}

/*
 * Post the struct inode info into an on-disk inode location in the
 * buffer-cache.  This gobbles the caller's reference to the
 * buffer_head in the inode location struct.
 *
 * The caller must have write access to iloc->bh.
 */
static int ext3_do_update_inode(handle_t *handle,
				struct inode *inode,
				struct ext3_iloc *iloc)
{
	struct ext3_inode *raw_inode = ext3_raw_inode(iloc);
	struct ext3_inode_info *ei = EXT3_I(inode);
	struct buffer_head *bh = iloc->bh;
	int err = 0, rc, block;
	int need_datasync = 0;
	__le32 disksize;
	uid_t i_uid;
	gid_t i_gid;

again:
	/* we can't allow multiple procs in here at once, its a bit racey */
	lock_buffer(bh);

	/* For fields not not tracking in the in-memory inode,
	 * initialise them to zero for new inodes. */
	if (ext3_test_inode_state(inode, EXT3_STATE_NEW))
		memset(raw_inode, 0, EXT3_SB(inode->i_sb)->s_inode_size);

	ext3_get_inode_flags(ei);
	raw_inode->i_mode = cpu_to_le16(inode->i_mode);
	i_uid = i_uid_read(inode);
	i_gid = i_gid_read(inode);
	if(!(test_opt(inode->i_sb, NO_UID32))) {
		raw_inode->i_uid_low = cpu_to_le16(low_16_bits(i_uid));
		raw_inode->i_gid_low = cpu_to_le16(low_16_bits(i_gid));
/*
 * Fix up interoperability with old kernels. Otherwise, old inodes get
 * re-used with the upper 16 bits of the uid/gid intact
 */
		if(!ei->i_dtime) {
			raw_inode->i_uid_high =
				cpu_to_le16(high_16_bits(i_uid));
			raw_inode->i_gid_high =
				cpu_to_le16(high_16_bits(i_gid));
		} else {
			raw_inode->i_uid_high = 0;
			raw_inode->i_gid_high = 0;
		}
	} else {
		raw_inode->i_uid_low =
			cpu_to_le16(fs_high2lowuid(i_uid));
		raw_inode->i_gid_low =
			cpu_to_le16(fs_high2lowgid(i_gid));
		raw_inode->i_uid_high = 0;
		raw_inode->i_gid_high = 0;
	}
	raw_inode->i_links_count = cpu_to_le16(inode->i_nlink);
	disksize = cpu_to_le32(ei->i_disksize);
	if (disksize != raw_inode->i_size) {
		need_datasync = 1;
		raw_inode->i_size = disksize;
	}
	raw_inode->i_atime = cpu_to_le32(inode->i_atime.tv_sec);
	raw_inode->i_ctime = cpu_to_le32(inode->i_ctime.tv_sec);
	raw_inode->i_mtime = cpu_to_le32(inode->i_mtime.tv_sec);
	raw_inode->i_blocks = cpu_to_le32(inode->i_blocks);
	raw_inode->i_dtime = cpu_to_le32(ei->i_dtime);
	raw_inode->i_flags = cpu_to_le32(ei->i_flags);
#ifdef EXT3_FRAGMENTS
	raw_inode->i_faddr = cpu_to_le32(ei->i_faddr);
	raw_inode->i_frag = ei->i_frag_no;
	raw_inode->i_fsize = ei->i_frag_size;
#endif
	raw_inode->i_file_acl = cpu_to_le32(ei->i_file_acl);
	if (!S_ISREG(inode->i_mode)) {
		raw_inode->i_dir_acl = cpu_to_le32(ei->i_dir_acl);
	} else {
		disksize = cpu_to_le32(ei->i_disksize >> 32);
		if (disksize != raw_inode->i_size_high) {
			raw_inode->i_size_high = disksize;
			need_datasync = 1;
		}
		if (ei->i_disksize > 0x7fffffffULL) {
			struct super_block *sb = inode->i_sb;
			if (!EXT3_HAS_RO_COMPAT_FEATURE(sb,
					EXT3_FEATURE_RO_COMPAT_LARGE_FILE) ||
			    EXT3_SB(sb)->s_es->s_rev_level ==
					cpu_to_le32(EXT3_GOOD_OLD_REV)) {
			       /* If this is the first large file
				* created, add a flag to the superblock.
				*/
				unlock_buffer(bh);
				err = ext3_journal_get_write_access(handle,
						EXT3_SB(sb)->s_sbh);
				if (err)
					goto out_brelse;

				ext3_update_dynamic_rev(sb);
				EXT3_SET_RO_COMPAT_FEATURE(sb,
					EXT3_FEATURE_RO_COMPAT_LARGE_FILE);
				handle->h_sync = 1;
				err = ext3_journal_dirty_metadata(handle,
						EXT3_SB(sb)->s_sbh);
				/* get our lock and start over */
				goto again;
			}
		}
	}
	raw_inode->i_generation = cpu_to_le32(inode->i_generation);
	if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode)) {
		if (old_valid_dev(inode->i_rdev)) {
			raw_inode->i_block[0] =
				cpu_to_le32(old_encode_dev(inode->i_rdev));
			raw_inode->i_block[1] = 0;
		} else {
			raw_inode->i_block[0] = 0;
			raw_inode->i_block[1] =
				cpu_to_le32(new_encode_dev(inode->i_rdev));
			raw_inode->i_block[2] = 0;
		}
	} else for (block = 0; block < EXT3_N_BLOCKS; block++)
		raw_inode->i_block[block] = ei->i_data[block];

	if (ei->i_extra_isize)
		raw_inode->i_extra_isize = cpu_to_le16(ei->i_extra_isize);

	BUFFER_TRACE(bh, "call ext3_journal_dirty_metadata");
	unlock_buffer(bh);
	rc = ext3_journal_dirty_metadata(handle, bh);
	if (!err)
		err = rc;
	ext3_clear_inode_state(inode, EXT3_STATE_NEW);

	atomic_set(&ei->i_sync_tid, handle->h_transaction->t_tid);
	if (need_datasync)
		atomic_set(&ei->i_datasync_tid, handle->h_transaction->t_tid);
out_brelse:
	brelse (bh);
	ext3_std_error(inode->i_sb, err);
	return err;
}

/*
 * ext3_write_inode()
 *
 * We are called from a few places:
 *
 * - Within generic_file_aio_write() -> generic_write_sync() for O_SYNC files.
 *   Here, there will be no transaction running. We wait for any running
 *   transaction to commit.
 *
 * - Within flush work (for sys_sync(), kupdate and such).
 *   We wait on commit, if told to.
 *
 * - Within iput_final() -> write_inode_now()
 *   We wait on commit, if told to.
 *
 * In all cases it is actually safe for us to return without doing anything,
 * because the inode has been copied into a raw inode buffer in
 * ext3_mark_inode_dirty().  This is a correctness thing for WB_SYNC_ALL
 * writeback.
 *
 * Note that we are absolutely dependent upon all inode dirtiers doing the
 * right thing: they *must* call mark_inode_dirty() after dirtying info in
 * which we are interested.
 *
 * It would be a bug for them to not do this.  The code:
 *
 *	mark_inode_dirty(inode)
 *	stuff();
 *	inode->i_size = expr;
 *
 * is in error because write_inode() could occur while `stuff()' is running,
 * and the new i_size will be lost.  Plus the inode will no longer be on the
 * superblock's dirty inode list.
 */
int ext3_write_inode(struct inode *inode, struct writeback_control *wbc)
{
	if (WARN_ON_ONCE(current->flags & PF_MEMALLOC))
		return 0;

	if (ext3_journal_current_handle()) {
		jbd_debug(1, "called recursively, non-PF_MEMALLOC!\n");
		dump_stack();
		return -EIO;
	}

	/*
	 * No need to force transaction in WB_SYNC_NONE mode. Also
	 * ext3_sync_fs() will force the commit after everything is
	 * written.
	 */
	if (wbc->sync_mode != WB_SYNC_ALL || wbc->for_sync)
		return 0;

	return ext3_force_commit(inode->i_sb);
}

/*
 * ext3_setattr()
 *
 * Called from notify_change.
 *
 * We want to trap VFS attempts to truncate the file as soon as
 * possible.  In particular, we want to make sure that when the VFS
 * shrinks i_size, we put the inode on the orphan list and modify
 * i_disksize immediately, so that during the subsequent flushing of
 * dirty pages and freeing of disk blocks, we can guarantee that any
 * commit will leave the blocks being flushed in an unused state on
 * disk.  (On recovery, the inode will get truncated and the blocks will
 * be freed, so we have a strong guarantee that no future commit will
 * leave these blocks visible to the user.)
 *
 * Called with inode->sem down.
 */
int ext3_setattr(struct dentry *dentry, struct iattr *attr)
{
	struct inode *inode = d_inode(dentry);
	int error, rc = 0;
	const unsigned int ia_valid = attr->ia_valid;

	error = inode_change_ok(inode, attr);
	if (error)
		return error;

	if (is_quota_modification(inode, attr))
		dquot_initialize(inode);
	if ((ia_valid & ATTR_UID && !uid_eq(attr->ia_uid, inode->i_uid)) ||
	    (ia_valid & ATTR_GID && !gid_eq(attr->ia_gid, inode->i_gid))) {
		handle_t *handle;

		/* (user+group)*(old+new) structure, inode write (sb,
		 * inode block, ? - but truncate inode update has it) */
		handle = ext3_journal_start(inode, EXT3_MAXQUOTAS_INIT_BLOCKS(inode->i_sb)+
					EXT3_MAXQUOTAS_DEL_BLOCKS(inode->i_sb)+3);
		if (IS_ERR(handle)) {
			error = PTR_ERR(handle);
			goto err_out;
		}
		error = dquot_transfer(inode, attr);
		if (error) {
			ext3_journal_stop(handle);
			return error;
		}
		/* Update corresponding info in inode so that everything is in
		 * one transaction */
		if (attr->ia_valid & ATTR_UID)
			inode->i_uid = attr->ia_uid;
		if (attr->ia_valid & ATTR_GID)
			inode->i_gid = attr->ia_gid;
		error = ext3_mark_inode_dirty(handle, inode);
		ext3_journal_stop(handle);
	}

	if (attr->ia_valid & ATTR_SIZE)
		inode_dio_wait(inode);

	if (S_ISREG(inode->i_mode) &&
	    attr->ia_valid & ATTR_SIZE && attr->ia_size < inode->i_size) {
		handle_t *handle;

		handle = ext3_journal_start(inode, 3);
		if (IS_ERR(handle)) {
			error = PTR_ERR(handle);
			goto err_out;
		}

		error = ext3_orphan_add(handle, inode);
		if (error) {
			ext3_journal_stop(handle);
			goto err_out;
		}
		EXT3_I(inode)->i_disksize = attr->ia_size;
		error = ext3_mark_inode_dirty(handle, inode);
		ext3_journal_stop(handle);
		if (error) {
			/* Some hard fs error must have happened. Bail out. */
			ext3_orphan_del(NULL, inode);
			goto err_out;
		}
		rc = ext3_block_truncate_page(inode, attr->ia_size);
		if (rc) {
			/* Cleanup orphan list and exit */
			handle = ext3_journal_start(inode, 3);
			if (IS_ERR(handle)) {
				ext3_orphan_del(NULL, inode);
				goto err_out;
			}
			ext3_orphan_del(handle, inode);
			ext3_journal_stop(handle);
			goto err_out;
		}
	}

	if ((attr->ia_valid & ATTR_SIZE) &&
	    attr->ia_size != i_size_read(inode)) {
		truncate_setsize(inode, attr->ia_size);
		ext3_truncate(inode);
	}

	setattr_copy(inode, attr);
	mark_inode_dirty(inode);

	if (ia_valid & ATTR_MODE)
		rc = posix_acl_chmod(inode, inode->i_mode);

err_out:
	ext3_std_error(inode->i_sb, error);
	if (!error)
		error = rc;
	return error;
}


/*
 * How many blocks doth make a writepage()?
 *
 * With N blocks per page, it may be:
 * N data blocks
 * 2 indirect block
 * 2 dindirect
 * 1 tindirect
 * N+5 bitmap blocks (from the above)
 * N+5 group descriptor summary blocks
 * 1 inode block
 * 1 superblock.
 * 2 * EXT3_SINGLEDATA_TRANS_BLOCKS for the quote files
 *
 * 3 * (N + 5) + 2 + 2 * EXT3_SINGLEDATA_TRANS_BLOCKS
 *
 * With ordered or writeback data it's the same, less the N data blocks.
 *
 * If the inode's direct blocks can hold an integral number of pages then a
 * page cannot straddle two indirect blocks, and we can only touch one indirect
 * and dindirect block, and the "5" above becomes "3".
 *
 * This still overestimates under most circumstances.  If we were to pass the
 * start and end offsets in here as well we could do block_to_path() on each
 * block and work out the exact number of indirects which are touched.  Pah.
 */

static int ext3_writepage_trans_blocks(struct inode *inode)
{
	int bpp = ext3_journal_blocks_per_page(inode);
	int indirects = (EXT3_NDIR_BLOCKS % bpp) ? 5 : 3;
	int ret;

	if (ext3_should_journal_data(inode))
		ret = 3 * (bpp + indirects) + 2;
	else
		ret = 2 * (bpp + indirects) + indirects + 2;

#ifdef CONFIG_QUOTA
	/* We know that structure was already allocated during dquot_initialize so
	 * we will be updating only the data blocks + inodes */
	ret += EXT3_MAXQUOTAS_TRANS_BLOCKS(inode->i_sb);
#endif

	return ret;
}

/*
 * The caller must have previously called ext3_reserve_inode_write().
 * Give this, we know that the caller already has write access to iloc->bh.
 */
int ext3_mark_iloc_dirty(handle_t *handle,
		struct inode *inode, struct ext3_iloc *iloc)
{
	int err = 0;

	/* the do_update_inode consumes one bh->b_count */
	get_bh(iloc->bh);

	/* ext3_do_update_inode() does journal_dirty_metadata */
	err = ext3_do_update_inode(handle, inode, iloc);
	put_bh(iloc->bh);
	return err;
}

/*
 * On success, We end up with an outstanding reference count against
 * iloc->bh.  This _must_ be cleaned up later.
 */

int
ext3_reserve_inode_write(handle_t *handle, struct inode *inode,
			 struct ext3_iloc *iloc)
{
	int err = 0;
	if (handle) {
		err = ext3_get_inode_loc(inode, iloc);
		if (!err) {
			BUFFER_TRACE(iloc->bh, "get_write_access");
			err = ext3_journal_get_write_access(handle, iloc->bh);
			if (err) {
				brelse(iloc->bh);
				iloc->bh = NULL;
			}
		}
	}
	ext3_std_error(inode->i_sb, err);
	return err;
}

/*
 * What we do here is to mark the in-core inode as clean with respect to inode
 * dirtiness (it may still be data-dirty).
 * This means that the in-core inode may be reaped by prune_icache
 * without having to perform any I/O.  This is a very good thing,
 * because *any* task may call prune_icache - even ones which
 * have a transaction open against a different journal.
 *
 * Is this cheating?  Not really.  Sure, we haven't written the
 * inode out, but prune_icache isn't a user-visible syncing function.
 * Whenever the user wants stuff synced (sys_sync, sys_msync, sys_fsync)
 * we start and wait on commits.
 */
int ext3_mark_inode_dirty(handle_t *handle, struct inode *inode)
{
	struct ext3_iloc iloc;
	int err;

	might_sleep();
	trace_ext3_mark_inode_dirty(inode, _RET_IP_);
	err = ext3_reserve_inode_write(handle, inode, &iloc);
	if (!err)
		err = ext3_mark_iloc_dirty(handle, inode, &iloc);
	return err;
}

/*
 * ext3_dirty_inode() is called from __mark_inode_dirty()
 *
 * We're really interested in the case where a file is being extended.
 * i_size has been changed by generic_commit_write() and we thus need
 * to include the updated inode in the current transaction.
 *
 * Also, dquot_alloc_space() will always dirty the inode when blocks
 * are allocated to the file.
 *
 * If the inode is marked synchronous, we don't honour that here - doing
 * so would cause a commit on atime updates, which we don't bother doing.
 * We handle synchronous inodes at the highest possible level.
 */
void ext3_dirty_inode(struct inode *inode, int flags)
{
	handle_t *current_handle = ext3_journal_current_handle();
	handle_t *handle;

	handle = ext3_journal_start(inode, 2);
	if (IS_ERR(handle))
		goto out;
	if (current_handle &&
		current_handle->h_transaction != handle->h_transaction) {
		/* This task has a transaction open against a different fs */
		printk(KERN_EMERG "%s: transactions do not match!\n",
		       __func__);
	} else {
		jbd_debug(5, "marking dirty.  outer handle=%p\n",
				current_handle);
		ext3_mark_inode_dirty(handle, inode);
	}
	ext3_journal_stop(handle);
out:
	return;
}

#if 0
/*
 * Bind an inode's backing buffer_head into this transaction, to prevent
 * it from being flushed to disk early.  Unlike
 * ext3_reserve_inode_write, this leaves behind no bh reference and
 * returns no iloc structure, so the caller needs to repeat the iloc
 * lookup to mark the inode dirty later.
 */
static int ext3_pin_inode(handle_t *handle, struct inode *inode)
{
	struct ext3_iloc iloc;

	int err = 0;
	if (handle) {
		err = ext3_get_inode_loc(inode, &iloc);
		if (!err) {
			BUFFER_TRACE(iloc.bh, "get_write_access");
			err = journal_get_write_access(handle, iloc.bh);
			if (!err)
				err = ext3_journal_dirty_metadata(handle,
								  iloc.bh);
			brelse(iloc.bh);
		}
	}
	ext3_std_error(inode->i_sb, err);
	return err;
}
#endif

int ext3_change_inode_journal_flag(struct inode *inode, int val)
{
	journal_t *journal;
	handle_t *handle;
	int err;

	/*
	 * We have to be very careful here: changing a data block's
	 * journaling status dynamically is dangerous.  If we write a
	 * data block to the journal, change the status and then delete
	 * that block, we risk forgetting to revoke the old log record
	 * from the journal and so a subsequent replay can corrupt data.
	 * So, first we make sure that the journal is empty and that
	 * nobody is changing anything.
	 */

	journal = EXT3_JOURNAL(inode);
	if (is_journal_aborted(journal))
		return -EROFS;

	journal_lock_updates(journal);
	journal_flush(journal);

	/*
	 * OK, there are no updates running now, and all cached data is
	 * synced to disk.  We are now in a completely consistent state
	 * which doesn't have anything in the journal, and we know that
	 * no filesystem updates are running, so it is safe to modify
	 * the inode's in-core data-journaling state flag now.
	 */

	if (val)
		EXT3_I(inode)->i_flags |= EXT3_JOURNAL_DATA_FL;
	else
		EXT3_I(inode)->i_flags &= ~EXT3_JOURNAL_DATA_FL;
	ext3_set_aops(inode);

	journal_unlock_updates(journal);

	/* Finally we can mark the inode as dirty. */

	handle = ext3_journal_start(inode, 1);
	if (IS_ERR(handle))
		return PTR_ERR(handle);

	err = ext3_mark_inode_dirty(handle, inode);
	handle->h_sync = 1;
	ext3_journal_stop(handle);
	ext3_std_error(inode->i_sb, err);

	return err;
}