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path: root/fs/file_table.c
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* Allow passing O_PATH descriptors via SCM_RIGHTS datagramsAl Viro2011-03-15
| | | | | | | | Just need to make sure that AF_UNIX garbage collector won't confuse O_PATHed socket on filesystem for real AF_UNIX opened socket. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* New kind of open files - "location only".Al Viro2011-03-15
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | New flag for open(2) - O_PATH. Semantics: * pathname is resolved, but the file itself is _NOT_ opened as far as filesystem is concerned. * almost all operations on the resulting descriptors shall fail with -EBADF. Exceptions are: 1) operations on descriptors themselves (i.e. close(), dup(), dup2(), dup3(), fcntl(fd, F_DUPFD), fcntl(fd, F_DUPFD_CLOEXEC, ...), fcntl(fd, F_GETFD), fcntl(fd, F_SETFD, ...)) 2) fcntl(fd, F_GETFL), for a common non-destructive way to check if descriptor is open 3) "dfd" arguments of ...at(2) syscalls, i.e. the starting points of pathname resolution * closing such descriptor does *NOT* affect dnotify or posix locks. * permissions are checked as usual along the way to file; no permission checks are applied to the file itself. Of course, giving such thing to syscall will result in permission checks (at the moment it means checking that starting point of ....at() is a directory and caller has exec permissions on it). fget() and fget_light() return NULL on such descriptors; use of fget_raw() and fget_raw_light() is needed to get them. That protects existing code from dealing with those things. There are two things still missing (they come in the next commits): one is handling of symlinks (right now we refuse to open them that way; see the next commit for semantics related to those) and another is descriptor passing via SCM_RIGHTS datagrams. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* CRED: Fix kernel panic upon security_file_alloc() failure.Tetsuo Handa2011-02-04
| | | | | | | | | | | | In get_empty_filp() since 2.6.29, file_free(f) is called with f->f_cred == NULL when security_file_alloc() returned an error. As a result, kernel will panic() due to put_cred(NULL) call within RCU callback. Fix this bug by assigning f->f_cred before calling security_file_alloc(). Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* fs: Remove unlikely() from fget_light()Steven Rostedt2011-01-17
| | | | | | | | | | | | | | | | There's an unlikely() in fget_light() that assumes the file ref count will be 1. Running the annotate branch profiler on a desktop that is performing daily tasks (running firefox, evolution, xchat and is also part of a distcc farm), it shows that the ref count is not 1 that often. correct incorrect % Function File Line ------- --------- - -------- ---- ---- 1035099358 6209599193 85 fget_light file_table.c 315 Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Christoph Hellwig <hch@lst.de> Signed-off-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* fs: allow for more than 2^31 filesEric Dumazet2010-10-26
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Robin Holt tried to boot a 16TB system and found af_unix was overflowing a 32bit value : <quote> We were seeing a failure which prevented boot. The kernel was incapable of creating either a named pipe or unix domain socket. This comes down to a common kernel function called unix_create1() which does: atomic_inc(&unix_nr_socks); if (atomic_read(&unix_nr_socks) > 2 * get_max_files()) goto out; The function get_max_files() is a simple return of files_stat.max_files. files_stat.max_files is a signed integer and is computed in fs/file_table.c's files_init(). n = (mempages * (PAGE_SIZE / 1024)) / 10; files_stat.max_files = n; In our case, mempages (total_ram_pages) is approx 3,758,096,384 (0xe0000000). That leaves max_files at approximately 1,503,238,553. This causes 2 * get_max_files() to integer overflow. </quote> Fix is to let /proc/sys/fs/file-nr & /proc/sys/fs/file-max use long integers, and change af_unix to use an atomic_long_t instead of atomic_t. get_max_files() is changed to return an unsigned long. get_nr_files() is changed to return a long. unix_nr_socks is changed from atomic_t to atomic_long_t, while not strictly needed to address Robin problem. Before patch (on a 64bit kernel) : # echo 2147483648 >/proc/sys/fs/file-max # cat /proc/sys/fs/file-max -18446744071562067968 After patch: # echo 2147483648 >/proc/sys/fs/file-max # cat /proc/sys/fs/file-max 2147483648 # cat /proc/sys/fs/file-nr 704 0 2147483648 Reported-by: Robin Holt <holt@sgi.com> Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com> Acked-by: David Miller <davem@davemloft.net> Reviewed-by: Robin Holt <holt@sgi.com> Tested-by: Robin Holt <holt@sgi.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Christoph Hellwig <hch@lst.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* fs: scale files_lockNick Piggin2010-08-18
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | fs: scale files_lock Improve scalability of files_lock by adding per-cpu, per-sb files lists, protected with an lglock. The lglock provides fast access to the per-cpu lists to add and remove files. It also provides a snapshot of all the per-cpu lists (although this is very slow). One difficulty with this approach is that a file can be removed from the list by another CPU. We must track which per-cpu list the file is on with a new variale in the file struct (packed into a hole on 64-bit archs). Scalability could suffer if files are frequently removed from different cpu's list. However loads with frequent removal of files imply short interval between adding and removing the files, and the scheduler attempts to avoid moving processes too far away. Also, even in the case of cross-CPU removal, the hardware has much more opportunity to parallelise cacheline transfers with N cachelines than with 1. A worst-case test of 1 CPU allocating files subsequently being freed by N CPUs degenerates to contending on a single lock, which is no worse than before. When more than one CPU are allocating files, even if they are always freed by different CPUs, there will be more parallelism than the single-lock case. Testing results: On a 2 socket, 8 core opteron, I measure the number of times the lock is taken to remove the file, the number of times it is removed by the same CPU that added it, and the number of times it is removed by the same node that added it. Booting: locks= 25049 cpu-hits= 23174 (92.5%) node-hits= 23945 (95.6%) kbuild -j16 locks=2281913 cpu-hits=2208126 (96.8%) node-hits=2252674 (98.7%) dbench 64 locks=4306582 cpu-hits=4287247 (99.6%) node-hits=4299527 (99.8%) So a file is removed from the same CPU it was added by over 90% of the time. It remains within the same node 95% of the time. Tim Chen ran some numbers for a 64 thread Nehalem system performing a compile. throughput 2.6.34-rc2 24.5 +patch 24.9 us sys idle IO wait (in %) 2.6.34-rc2 51.25 28.25 17.25 3.25 +patch 53.75 18.5 19 8.75 So significantly less CPU time spent in kernel code, higher idle time and slightly higher throughput. Single threaded performance difference was within the noise of microbenchmarks. That is not to say penalty does not exist, the code is larger and more memory accesses required so it will be slightly slower. Cc: linux-kernel@vger.kernel.org Cc: Tim Chen <tim.c.chen@linux.intel.com> Cc: Andi Kleen <ak@linux.intel.com> Signed-off-by: Nick Piggin <npiggin@kernel.dk> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* fs: cleanup files_lock lockingNick Piggin2010-08-18
| | | | | | | | | | | | | | | fs: cleanup files_lock locking Lock tty_files with a new spinlock, tty_files_lock; provide helpers to manipulate the per-sb files list; unexport the files_lock spinlock. Cc: linux-kernel@vger.kernel.org Cc: Christoph Hellwig <hch@infradead.org> Cc: Alan Cox <alan@lxorguk.ukuu.org.uk> Acked-by: Andi Kleen <ak@linux.intel.com> Acked-by: Greg Kroah-Hartman <gregkh@suse.de> Signed-off-by: Nick Piggin <npiggin@kernel.dk> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* Revert "fsnotify: store struct file not struct path"Linus Torvalds2010-08-12
| | | | | | | | | | | | | | | This reverts commit 3bcf3860a4ff9bbc522820b4b765e65e4deceb3e (and the accompanying commit c1e5c954020e "vfs/fsnotify: fsnotify_close can delay the final work in fput" that was a horribly ugly hack to make it work at all). The 'struct file' approach not only causes that disgusting hack, it somehow breaks pulseaudio, probably due to some other subtlety with f_count handling. Fix up various conflicts due to later fsnotify work. Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* vfs: improve comment describing fget_light()Tony Battersby2010-08-11
| | | | | | | | | | Improve the description of fget_light(), which is currently incorrect about needing a prior refcnt (judging by the way it is actually used). Signed-off-by: Tony Battersby <tonyb@cybernetics.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* vfs/fsnotify: fsnotify_close can delay the final work in fputEric Paris2010-07-28
| | | | | | | | | | | | | | | | | | | | | | | | | | fanotify almost works like so: user context calls fsnotify_* function with a struct file. fsnotify takes a reference on the struct path user context goes about it's buissiness at some later point in time the fsnotify listener gets the struct path fanotify listener calls dentry_open() to create a file which userspace can deal with listener drops the reference on the struct path at some later point the listener calls close() on it's new file With the switch from struct path to struct file this presents a problem for fput() and fsnotify_close(). fsnotify_close() is called when the filp has already reached 0 and __fput() wants to do it's cleanup. The solution presented here is a bit odd. If an event is created from a struct file we take a reference on the file. We check however if the f_count was already 0 and if so we take an EXTRA reference EVEN THOUGH IT WAS ZERO. In __fput() (where we know the f_count hit 0 once) we check if the f_count is non-zero and if so we drop that 'extra' ref and return without destroying the file. Signed-off-by: Eric Paris <eparis@redhat.com>
* get rid of the magic around f_count in aioAl Viro2010-05-27
| | | | | | | | | | | | | | | | | | | | | | | | | __aio_put_req() plays sick games with file refcount. What it wants is fput() from atomic context; it's almost always done with f_count > 1, so they only have to deal with delayed work in rare cases when their reference happens to be the last one. Current code decrements f_count and if it hasn't hit 0, everything is fine. Otherwise it keeps a pointer to struct file (with zero f_count!) around and has delayed work do __fput() on it. Better way to do it: use atomic_long_add_unless( , -1, 1) instead of !atomic_long_dec_and_test(). IOW, decrement it only if it's not the last reference, leave refcount alone if it was. And use normal fput() in delayed work. I've made that atomic_long_add_unless call a new helper - fput_atomic(). Drops a reference to file if it's safe to do in atomic (i.e. if that's not the last one), tells if it had been able to do that. aio.c converted to it, __fput() use is gone. req->ki_file *always* contributes to refcount now. And __fput() became static. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* vfs: take f_lock on modifying f_mode after open timeWu Fengguang2010-03-06
| | | | | | | | | | | | | | We'll introduce FMODE_RANDOM which will be runtime modified. So protect all runtime modification to f_mode with f_lock to avoid races. Signed-off-by: Wu Fengguang <fengguang.wu@intel.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Christoph Hellwig <hch@infradead.org> Cc: Trond Myklebust <Trond.Myklebust@netapp.com> Cc: Chuck Lever <chuck.lever@oracle.com> Cc: <stable@kernel.org> [2.6.33.x] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Take ima_file_free() to proper place.Al Viro2010-02-07
| | | | | | Hooks: Just Say No. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* alloc_file(): simplify handling of mnt_clone_write() errorsRoland Dreier2009-12-22
| | | | | | | | | | When alloc_file() and init_file() were combined, the error handling of mnt_clone_write() was taken into alloc_file() in a somewhat obfuscated way. Since we don't use the error code for anything except warning, we might as well warn directly without an extra variable. Signed-off-by: Roland Dreier <rolandd@cisco.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* re-export alloc_file()Roland Dreier2009-12-16
| | | | | | | | | | | | | | | | | | Commit 3d1e4631 ("get rid of init_file()") removed the export of alloc_file() -- possibly inadvertently, since that commit mainly consisted of deleting the lines between the end of alloc_file() and the start of the code in init_file(). There is in fact one modular use of alloc_file() in the tree, in drivers/infiniband/core/uverbs_main.c, so re-add the export to fix: ERROR: "alloc_file" [drivers/infiniband/core/ib_uverbs.ko] undefined! when CONFIG_INFINIBAND_USER_ACCESS=m. Cc: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Roland Dreier <rolandd@cisco.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Untangling ima mess, part 1: alloc_file()Al Viro2009-12-16
| | | | | | | | | | There are 2 groups of alloc_file() callers: * ones that are followed by ima_counts_get * ones giving non-regular files So let's pull that ima_counts_get() into alloc_file(); it's a no-op in case of non-regular files. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* fs: move get_empty_filp() deffinition to internal.hEric Paris2009-12-16
| | | | | | | | | | | | All users outside of fs/ of get_empty_filp() have been removed. This patch moves the definition from the include/ directory to internal.h so no new users crop up and removes the EXPORT_SYMBOL. I'd love to see open intents stop using it too, but that's a problem for another day and a smarter developer! Signed-off-by: Eric Paris <eparis@redhat.com> Acked-by: Miklos Szeredi <miklos@szeredi.hu> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* switch alloc_file() to passing struct pathAl Viro2009-12-16
| | | | | | | ... and have the caller grab both mnt and dentry; kill leak in infiniband, while we are at it. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* get rid of init_file()Al Viro2009-12-16
| | | | Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* unexport get_empty_filp()Al Viro2009-12-16
| | | | Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* LSM: imbed ima calls in the security hooksMimi Zohar2009-10-25
| | | | | | | | | Based on discussions on LKML and LSM, where there are consecutive security_ and ima_ calls in the vfs layer, move the ima_ calls to the existing security_ hooks. Signed-off-by: Mimi Zohar <zohar@us.ibm.com> Signed-off-by: James Morris <jmorris@namei.org>
* sysctl: remove "struct file *" argument of ->proc_handlerAlexey Dobriyan2009-09-24
| | | | | | | | | | | | | | | | | | | | | It's unused. It isn't needed -- read or write flag is already passed and sysctl shouldn't care about the rest. It _was_ used in two places at arch/frv for some reason. Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Cc: David Howells <dhowells@redhat.com> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: "David S. Miller" <davem@davemloft.net> Cc: James Morris <jmorris@namei.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* fs: move mark_files_ro into file_table.cnpiggin@suse.de2009-06-11
| | | | | | | | | | | This function walks the s_files lock, and operates primarily on the files in a superblock, so it better belongs here (eg. see also fs_may_remount_ro). [AV: ... and it shouldn't be static after that move] Signed-off-by: Nick Piggin <npiggin@suse.de> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* fs: introduce mnt_clone_writenpiggin@suse.de2009-06-11
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch speeds up lmbench lat_mmap test by about another 2% after the first patch. Before: avg = 462.286 std = 5.46106 After: avg = 453.12 std = 9.58257 (50 runs of each, stddev gives a reasonable confidence) It does this by introducing mnt_clone_write, which avoids some heavyweight operations of mnt_want_write if called on a vfsmount which we know already has a write count; and mnt_want_write_file, which can call mnt_clone_write if the file is open for write. After these two patches, mnt_want_write and mnt_drop_write go from 7% on the profile down to 1.3% (including mnt_clone_write). [AV: mnt_want_write_file() should take file alone and derive mnt from it; not only all callers have that form, but that's the only mnt about which we know that it's already held for write if file is opened for write] Cc: Dave Hansen <haveblue@us.ibm.com> Signed-off-by: Nick Piggin <npiggin@suse.de> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* trivial: remove unused variable 'path' in alloc_file()Tero Roponen2009-03-30
| | | | | | | 'struct path' is not used in alloc_file(). Signed-off-by: Tero Roponen <tero.roponen@gmail.com> Signed-off-by: Jiri Kosina <jkosina@suse.cz>
* Merge branch 'bkl-removal' of git://git.lwn.net/linux-2.6Linus Torvalds2009-03-26
|\ | | | | | | | | | | | | | | * 'bkl-removal' of git://git.lwn.net/linux-2.6: Rationalize fasync return values Move FASYNC bit handling to f_op->fasync() Use f_lock to protect f_flags Rename struct file->f_ep_lock
| * Rename struct file->f_ep_lockJonathan Corbet2009-03-16
| | | | | | | | | | | | | | | | | | | | This lock moves out of the CONFIG_EPOLL ifdef and becomes f_lock. For now, epoll remains the only user, but a future patch will use it to protect f_flags as well. Cc: Davide Libenzi <davidel@xmailserver.org> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jonathan Corbet <corbet@lwn.net>
* | Merge branch 'master' into nextJames Morris2009-02-05
|\| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Conflicts: fs/namei.c Manually merged per: diff --cc fs/namei.c index 734f2b5,bbc15c2..0000000 --- a/fs/namei.c +++ b/fs/namei.c @@@ -860,9 -848,8 +849,10 @@@ static int __link_path_walk(const char nd->flags |= LOOKUP_CONTINUE; err = exec_permission_lite(inode); if (err == -EAGAIN) - err = vfs_permission(nd, MAY_EXEC); + err = inode_permission(nd->path.dentry->d_inode, + MAY_EXEC); + if (!err) + err = ima_path_check(&nd->path, MAY_EXEC); if (err) break; @@@ -1525,14 -1506,9 +1509,14 @@@ int may_open(struct path *path, int acc flag &= ~O_TRUNC; } - error = vfs_permission(nd, acc_mode); + error = inode_permission(inode, acc_mode); if (error) return error; + - error = ima_path_check(&nd->path, ++ error = ima_path_check(path, + acc_mode & (MAY_READ | MAY_WRITE | MAY_EXEC)); + if (error) + return error; /* * An append-only file must be opened in append mode for writing. */ Signed-off-by: James Morris <jmorris@namei.org>
| * filp_cachep can be static in fs/file_table.cEric Dumazet2008-12-31
| | | | | | | | | | | | | | | | | | | | | | Instead of creating the "filp" kmem_cache in vfs_caches_init(), we can do it a litle be later in files_init(), so that filp_cachep is static to fs/file_table.c Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Signed-off-by: Eric Dumazet <dada1@cosmosbay.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* | integrity: IMA hooksMimi Zohar2009-02-05
|/ | | | | | | | | | This patch replaces the generic integrity hooks, for which IMA registered itself, with IMA integrity hooks in the appropriate places directly in the fs directory. Signed-off-by: Mimi Zohar <zohar@us.ibm.com> Acked-by: Serge Hallyn <serue@us.ibm.com> Signed-off-by: James Morris <jmorris@namei.org>
* CRED: Use creds in file structsDavid Howells2008-11-13
| | | | | | | | | | | | Attach creds to file structs and discard f_uid/f_gid. file_operations::open() methods (such as hppfs_open()) should use file->f_cred rather than current_cred(). At the moment file->f_cred will be current_cred() at this point. Signed-off-by: David Howells <dhowells@redhat.com> Reviewed-by: James Morris <jmorris@namei.org> Signed-off-by: James Morris <jmorris@namei.org>
* CRED: Wrap current->cred and a few other accessorsDavid Howells2008-11-13
| | | | | | | | | | Wrap current->cred and a few other accessors to hide their actual implementation. Signed-off-by: David Howells <dhowells@redhat.com> Acked-by: James Morris <jmorris@namei.org> Acked-by: Serge Hallyn <serue@us.ibm.com> Signed-off-by: James Morris <jmorris@namei.org>
* CRED: Separate task security context from task_structDavid Howells2008-11-13
| | | | | | | | | | | | | | | | Separate the task security context from task_struct. At this point, the security data is temporarily embedded in the task_struct with two pointers pointing to it. Note that the Alpha arch is altered as it refers to (E)UID and (E)GID in entry.S via asm-offsets. With comment fixes Signed-off-by: Marc Dionne <marc.c.dionne@gmail.com> Signed-off-by: David Howells <dhowells@redhat.com> Acked-by: James Morris <jmorris@namei.org> Acked-by: Serge Hallyn <serue@us.ibm.com> Signed-off-by: James Morris <jmorris@namei.org>
* saner FASYNC handling on file closeAl Viro2008-11-01
| | | | | | | | | | | | | | As it is, all instances of ->release() for files that have ->fasync() need to remember to evict file from fasync lists; forgetting that creates a hole and we actually have a bunch that *does* forget. So let's keep our lives simple - let __fput() check FASYNC in file->f_flags and call ->fasync() there if it's been set. And lose that crap in ->release() instances - leaving it there is still valid, but we don't have to bother anymore. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* [PATCH] introduce fmode_t, do annotationsAl Viro2008-10-21
| | | | Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* [PATCH] f_count may wrap aroundAl Viro2008-07-26
| | | | | | | make it atomic_long_t; while we are at it, get rid of useless checks in affs, hfs and hpfs - ->open() always has it equal to 1, ->release() - to 0. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* [PATCH] split linux/file.hAl Viro2008-05-01
| | | | | | Initial splitoff of the low-level stuff; taken to fdtable.h Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* [PATCH] r/o bind mounts: debugging for missed callsDave Hansen2008-04-19
| | | | | | | | | | | | | | | | | | | | | | | | There have been a few oopses caused by 'struct file's with NULL f_vfsmnts. There was also a set of potentially missed mnt_want_write()s from dentry_open() calls. This patch provides a very simple debugging framework to catch these kinds of bugs. It will WARN_ON() them, but should stop us from having any oopses or mnt_writer count imbalances. I'm quite convinced that this is a good thing because it found bugs in the stuff I was working on as soon as I wrote it. [hch: made it conditional on a debug option. But it's still a little bit too ugly] [hch: merged forced remount r/o fix from Dave and akpm's fix for the fix] Signed-off-by: Dave Hansen <haveblue@us.ibm.com> Acked-by: Al Viro <viro@ZenIV.linux.org.uk> Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* [PATCH] r/o bind mounts: elevate write count for open()sDave Hansen2008-04-19
| | | | | | | | | | | | | | | | | | | | | | | | This is the first really tricky patch in the series. It elevates the writer count on a mount each time a non-special file is opened for write. We used to do this in may_open(), but Miklos pointed out that __dentry_open() is used as well to create filps. This will cover even those cases, while a call in may_open() would not have. There is also an elevated count around the vfs_create() call in open_namei(). See the comments for more details, but we need this to fix a 'create, remount, fail r/w open()' race. Some filesystems forego the use of normal vfs calls to create struct files. Make sure that these users elevate the mnt writer count because they will get __fput(), and we need to make sure they're balanced. Acked-by: Al Viro <viro@ZenIV.linux.org.uk> Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Dave Hansen <haveblue@us.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* [PATCH] r/o bind mounts: create helper to drop file write accessDave Hansen2008-04-19
| | | | | | | | | | | | | | | | | | | If someone decides to demote a file from r/w to just r/o, they can use this same code as __fput(). NFS does just that, and will use this in the next patch. AV: drop write access in __fput() only after we evict from file list. Signed-off-by: Dave Hansen <haveblue@us.ibm.com> Cc: Erez Zadok <ezk@cs.sunysb.edu> Cc: Trond Myklebust <trond.myklebust@fys.uio.no> Cc: "J Bruce Fields" <bfields@fieldses.org> Acked-by: Al Viro <viro@ZenIV.linux.org.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* [PATCH] fix up new filp allocatorsDave Hansen2008-03-19
| | | | | | | | | | | | | | | | | | | Some new uses of get_empty_filp() have crept in; switched to alloc_file() to make sure that pieces of initialization won't be missing. We really need to kill get_empty_filp(). [AV] fixed dentry leak on failure exit in anon_inode_getfd() Cc: Erez Zadok <ezk@cs.sunysb.edu> Cc: Trond Myklebust <trond.myklebust@fys.uio.no> Cc: "J Bruce Fields" <bfields@fieldses.org> Acked-by: Al Viro <viro@ZenIV.linux.org.uk> Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Dave Hansen <haveblue@us.ibm.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* fs: remove fastcall, it is always emptyHarvey Harrison2008-02-08
| | | | | | | [akpm@linux-foundation.org: coding-style fixes] Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* fs/file_table.c: use list_for_each_entry() instead of list_for_each()Matthias Kaehlcke2007-10-19
| | | | | | | | | fs/file_table.c: use list_for_each_entry() instead of list_for_each() in fs_may_remount_ro() Signed-off-by: Matthias Kaehlcke <matthias.kaehlcke@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* r/o bind mounts: filesystem helpers for custom 'struct file'sDave Hansen2007-10-17
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Why do we need r/o bind mounts? This feature allows a read-only view into a read-write filesystem. In the process of doing that, it also provides infrastructure for keeping track of the number of writers to any given mount. This has a number of uses. It allows chroots to have parts of filesystems writable. It will be useful for containers in the future because users may have root inside a container, but should not be allowed to write to somefilesystems. This also replaces patches that vserver has had out of the tree for several years. It allows security enhancement by making sure that parts of your filesystem read-only (such as when you don't trust your FTP server), when you don't want to have entire new filesystems mounted, or when you want atime selectively updated. I've been using the following script to test that the feature is working as desired. It takes a directory and makes a regular bind and a r/o bind mount of it. It then performs some normal filesystem operations on the three directories, including ones that are expected to fail, like creating a file on the r/o mount. This patch: Some filesystems forego the vfs and may_open() and create their own 'struct file's. This patch creates a couple of helper functions which can be used by these filesystems, and will provide a unified place which the r/o bind mount code may patch. Also, rename an existing, static-scope init_file() to a less generic name. Signed-off-by: Dave Hansen <haveblue@us.ibm.com> Cc: Christoph Hellwig <hch@lst.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* fs: use kmem_cache_zalloc insteadDenis Cheng2007-10-17
| | | | | | Signed-off-by: Denis Cheng <crquan@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* lib: percpu_counter_sum_positivePeter Zijlstra2007-10-17
| | | | | | | | | | s/percpu_counter_sum/&_positive/ Because its consitent with percpu_counter_read* Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* header cleaning: don't include smp_lock.h when not usedRandy Dunlap2007-05-08
| | | | | | | | | | | | Remove includes of <linux/smp_lock.h> where it is not used/needed. Suggested by Al Viro. Builds cleanly on x86_64, i386, alpha, ia64, powerpc, sparc, sparc64, and arm (all 59 defconfigs). Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* [PATCH] VFS: change struct file to use struct pathJosef "Jeff" Sipek2006-12-08
| | | | | | | | | | | | | This patch changes struct file to use struct path instead of having independent pointers to struct dentry and struct vfsmount, and converts all users of f_{dentry,vfsmnt} in fs/ to use f_path.{dentry,mnt}. Additionally, it adds two #define's to make the transition easier for users of the f_dentry and f_vfsmnt. Signed-off-by: Josef "Jeff" Sipek <jsipek@cs.sunysb.edu> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] file: modify struct fown_struct to use a struct pidEric W. Biederman2006-10-02
| | | | | | | | | | File handles can be requested to send sigio and sigurg to processes. By tracking the destination processes using struct pid instead of pid_t we make the interface safe from all potential pid wrap around problems. Signed-off-by: Eric W. Biederman <ebiederm@xmission.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] inode-diet: Move i_cdev into a unionTheodore Ts'o2006-09-27
| | | | | | | | Move the i_cdev pointer in struct inode into a union. Signed-off-by: "Theodore Ts'o" <tytso@mit.edu> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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