diff options
author | Linus Torvalds <torvalds@linux-foundation.org> | 2009-04-01 13:57:49 -0400 |
---|---|---|
committer | Linus Torvalds <torvalds@linux-foundation.org> | 2009-04-01 13:57:49 -0400 |
commit | 395d73413c5656c6d7706ae91dcb441f9b7e3074 (patch) | |
tree | 7fadabe996f70d7918583fa2312d4fad19397fcb /Documentation/filesystems | |
parent | c226fd659fa7b6a7b038df5ae6856a68514bacde (diff) | |
parent | 06705bff9114531a997a7d0c2520bea0f2927410 (diff) |
Merge branch 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4
* 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4: (33 commits)
ext4: Regularize mount options
ext4: fix locking typo in mballoc which could cause soft lockup hangs
ext4: fix typo which causes a memory leak on error path
jbd2: Update locking coments
ext4: Rename pa_linear to pa_type
ext4: add checks of block references for non-extent inodes
ext4: Check for an valid i_mode when reading the inode from disk
ext4: Use WRITE_SYNC for commits which are caused by fsync()
ext4: Add auto_da_alloc mount option
ext4: Use struct flex_groups to calculate get_orlov_stats()
ext4: Use atomic_t's in struct flex_groups
ext4: remove /proc tuning knobs
ext4: Add sysfs support
ext4: Track lifetime disk writes
ext4: Fix discard of inode prealloc space with delayed allocation.
ext4: Automatically allocate delay allocated blocks on rename
ext4: Automatically allocate delay allocated blocks on close
ext4: add EXT4_IOC_ALLOC_DA_BLKS ioctl
ext4: Simplify delalloc code by removing mpage_da_writepages()
ext4: Save stack space by removing fake buffer heads
...
Diffstat (limited to 'Documentation/filesystems')
-rw-r--r-- | Documentation/filesystems/ext4.txt | 30 | ||||
-rw-r--r-- | Documentation/filesystems/proc.txt | 21 |
2 files changed, 27 insertions, 24 deletions
diff --git a/Documentation/filesystems/ext4.txt b/Documentation/filesystems/ext4.txt index cec829bc7291..97882df04865 100644 --- a/Documentation/filesystems/ext4.txt +++ b/Documentation/filesystems/ext4.txt | |||
@@ -85,7 +85,7 @@ Note: More extensive information for getting started with ext4 can be | |||
85 | * extent format more robust in face of on-disk corruption due to magics, | 85 | * extent format more robust in face of on-disk corruption due to magics, |
86 | * internal redundancy in tree | 86 | * internal redundancy in tree |
87 | * improved file allocation (multi-block alloc) | 87 | * improved file allocation (multi-block alloc) |
88 | * fix 32000 subdirectory limit | 88 | * lift 32000 subdirectory limit imposed by i_links_count[1] |
89 | * nsec timestamps for mtime, atime, ctime, create time | 89 | * nsec timestamps for mtime, atime, ctime, create time |
90 | * inode version field on disk (NFSv4, Lustre) | 90 | * inode version field on disk (NFSv4, Lustre) |
91 | * reduced e2fsck time via uninit_bg feature | 91 | * reduced e2fsck time via uninit_bg feature |
@@ -100,6 +100,9 @@ Note: More extensive information for getting started with ext4 can be | |||
100 | * efficent new ordered mode in JBD2 and ext4(avoid using buffer head to force | 100 | * efficent new ordered mode in JBD2 and ext4(avoid using buffer head to force |
101 | the ordering) | 101 | the ordering) |
102 | 102 | ||
103 | [1] Filesystems with a block size of 1k may see a limit imposed by the | ||
104 | directory hash tree having a maximum depth of two. | ||
105 | |||
103 | 2.2 Candidate features for future inclusion | 106 | 2.2 Candidate features for future inclusion |
104 | 107 | ||
105 | * Online defrag (patches available but not well tested) | 108 | * Online defrag (patches available but not well tested) |
@@ -180,8 +183,8 @@ commit=nrsec (*) Ext4 can be told to sync all its data and metadata | |||
180 | performance. | 183 | performance. |
181 | 184 | ||
182 | barrier=<0|1(*)> This enables/disables the use of write barriers in | 185 | barrier=<0|1(*)> This enables/disables the use of write barriers in |
183 | the jbd code. barrier=0 disables, barrier=1 enables. | 186 | barrier(*) the jbd code. barrier=0 disables, barrier=1 enables. |
184 | This also requires an IO stack which can support | 187 | nobarrier This also requires an IO stack which can support |
185 | barriers, and if jbd gets an error on a barrier | 188 | barriers, and if jbd gets an error on a barrier |
186 | write, it will disable again with a warning. | 189 | write, it will disable again with a warning. |
187 | Write barriers enforce proper on-disk ordering | 190 | Write barriers enforce proper on-disk ordering |
@@ -189,6 +192,9 @@ barrier=<0|1(*)> This enables/disables the use of write barriers in | |||
189 | safe to use, at some performance penalty. If | 192 | safe to use, at some performance penalty. If |
190 | your disks are battery-backed in one way or another, | 193 | your disks are battery-backed in one way or another, |
191 | disabling barriers may safely improve performance. | 194 | disabling barriers may safely improve performance. |
195 | The mount options "barrier" and "nobarrier" can | ||
196 | also be used to enable or disable barriers, for | ||
197 | consistency with other ext4 mount options. | ||
192 | 198 | ||
193 | inode_readahead=n This tuning parameter controls the maximum | 199 | inode_readahead=n This tuning parameter controls the maximum |
194 | number of inode table blocks that ext4's inode | 200 | number of inode table blocks that ext4's inode |
@@ -310,6 +316,24 @@ journal_ioprio=prio The I/O priority (from 0 to 7, where 0 is the | |||
310 | a slightly higher priority than the default I/O | 316 | a slightly higher priority than the default I/O |
311 | priority. | 317 | priority. |
312 | 318 | ||
319 | auto_da_alloc(*) Many broken applications don't use fsync() when | ||
320 | noauto_da_alloc replacing existing files via patterns such as | ||
321 | fd = open("foo.new")/write(fd,..)/close(fd)/ | ||
322 | rename("foo.new", "foo"), or worse yet, | ||
323 | fd = open("foo", O_TRUNC)/write(fd,..)/close(fd). | ||
324 | If auto_da_alloc is enabled, ext4 will detect | ||
325 | the replace-via-rename and replace-via-truncate | ||
326 | patterns and force that any delayed allocation | ||
327 | blocks are allocated such that at the next | ||
328 | journal commit, in the default data=ordered | ||
329 | mode, the data blocks of the new file are forced | ||
330 | to disk before the rename() operation is | ||
331 | commited. This provides roughly the same level | ||
332 | of guarantees as ext3, and avoids the | ||
333 | "zero-length" problem that can happen when a | ||
334 | system crashes before the delayed allocation | ||
335 | blocks are forced to disk. | ||
336 | |||
313 | Data Mode | 337 | Data Mode |
314 | ========= | 338 | ========= |
315 | There are 3 different data modes: | 339 | There are 3 different data modes: |
diff --git a/Documentation/filesystems/proc.txt b/Documentation/filesystems/proc.txt index 830bad7cce0f..efc4fd9f40ce 100644 --- a/Documentation/filesystems/proc.txt +++ b/Documentation/filesystems/proc.txt | |||
@@ -940,27 +940,6 @@ Table 1-10: Files in /proc/fs/ext4/<devname> | |||
940 | File Content | 940 | File Content |
941 | mb_groups details of multiblock allocator buddy cache of free blocks | 941 | mb_groups details of multiblock allocator buddy cache of free blocks |
942 | mb_history multiblock allocation history | 942 | mb_history multiblock allocation history |
943 | stats controls whether the multiblock allocator should start | ||
944 | collecting statistics, which are shown during the unmount | ||
945 | group_prealloc the multiblock allocator will round up allocation | ||
946 | requests to a multiple of this tuning parameter if the | ||
947 | stripe size is not set in the ext4 superblock | ||
948 | max_to_scan The maximum number of extents the multiblock allocator | ||
949 | will search to find the best extent | ||
950 | min_to_scan The minimum number of extents the multiblock allocator | ||
951 | will search to find the best extent | ||
952 | order2_req Tuning parameter which controls the minimum size for | ||
953 | requests (as a power of 2) where the buddy cache is | ||
954 | used | ||
955 | stream_req Files which have fewer blocks than this tunable | ||
956 | parameter will have their blocks allocated out of a | ||
957 | block group specific preallocation pool, so that small | ||
958 | files are packed closely together. Each large file | ||
959 | will have its blocks allocated out of its own unique | ||
960 | preallocation pool. | ||
961 | inode_readahead Tuning parameter which controls the maximum number of | ||
962 | inode table blocks that ext4's inode table readahead | ||
963 | algorithm will pre-read into the buffer cache | ||
964 | .............................................................................. | 943 | .............................................................................. |
965 | 944 | ||
966 | 945 | ||