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2011-07-21fs: always maintain i_dio_countChristoph Hellwig3-24/+17
Maintain i_dio_count for all filesystems, not just those using DIO_LOCKING. This these filesystems to also protect truncate against direct I/O requests by using common code. Right now the only non-DIO_LOCKING filesystem that appears to do so is XFS, which uses an opencoded variant of the i_dio_count scheme. Behaviour doesn't change for filesystems never calling inode_dio_wait. For ext4 behaviour changes when using the dioread_nonlock option, which previously was missing any protection between truncate and direct I/O reads. For ocfs2 that handcrafted i_dio_count manipulations are replaced with the common code now enable. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2011-07-21fs: move inode_dio_wait calls into ->setattrChristoph Hellwig12-3/+24
Let filesystems handle waiting for direct I/O requests themselves instead of doing it beforehand. This means filesystem-specific locks to prevent new dio referenes from appearing can be held. This is important to allow generalizing i_dio_count to non-DIO_LOCKING filesystems. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2011-07-21fs: kill i_alloc_semChristoph Hellwig8-44/+67
i_alloc_sem is a rather special rw_semaphore. It's the last one that may be released by a non-owner, and it's write side is always mirrored by real exclusion. It's intended use it to wait for all pending direct I/O requests to finish before starting a truncate. Replace it with a hand-grown construct: - exclusion for truncates is already guaranteed by i_mutex, so it can simply fall way - the reader side is replaced by an i_dio_count member in struct inode that counts the number of pending direct I/O requests. Truncate can't proceed as long as it's non-zero - when i_dio_count reaches non-zero we wake up a pending truncate using wake_up_bit on a new bit in i_flags - new references to i_dio_count can't appear while we are waiting for it to read zero because the direct I/O count always needs i_mutex (or an equivalent like XFS's i_iolock) for starting a new operation. This scheme is much simpler, and saves the space of a spinlock_t and a struct list_head in struct inode (typically 160 bits on a non-debug 64-bit system). Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2011-07-21fs: simplify handling of zero sized reads in __blockdev_direct_IOChristoph Hellwig1-2/+5
Reject zero sized reads as soon as we know our I/O length, and don't borther with locks or allocations that might have to be cleaned up otherwise. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2011-07-21ext4: Rewrite ext4_page_mkwrite() to use generic helpersJan Kara1-51/+55
Rewrite ext4_page_mkwrite() to use __block_page_mkwrite() helper. This removes the need of using i_alloc_sem to avoid races with truncate which seems to be the wrong locking order according to lock ordering documented in mm/rmap.c. Also calling ext4_da_write_begin() as used by the old code seems to be problematic because we can decide to flush delay-allocated blocks which will acquire s_umount semaphore - again creating unpleasant lock dependency if not directly a deadlock. Also add a check for frozen filesystem so that we don't busyloop in page fault when the filesystem is frozen. Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2011-07-21fat: remove i_alloc_sem abuseChristoph Hellwig3-2/+7
Add a new rw_semaphore to protect bmap against truncate. Previous i_alloc_sem was abused for this, but it's going away in this series. Note that we can't simply use i_mutex, given that the swapon code calls ->bmap under it. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2011-07-21VFS: Fixup kerneldoc for generic_permission()Tobias Klauser1-1/+0
The flags parameter went away in d749519b444db985e40b897f73ce1898b11f997e Signed-off-by: Tobias Klauser <tklauser@distanz.ch> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2011-07-21xfs: make use of new shrinker callout for the inode cacheDave Chinner3-56/+46
Convert the inode reclaim shrinker to use the new per-sb shrinker operations. This allows much bigger reclaim batches to be used, and allows the XFS inode cache to be shrunk in proportion with the VFS dentry and inode caches. This avoids the problem of the VFS caches being shrunk significantly before the XFS inode cache is shrunk resulting in imbalances in the caches during reclaim. Signed-off-by: Dave Chinner <dchinner@redhat.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2011-07-21vfs: increase shrinker batch sizeDave Chinner1-0/+1
Now that the per-sb shrinker is responsible for shrinking 2 or more caches, increase the batch size to keep econmies of scale for shrinking each cache. Increase the shrinker batch size to 1024 objects. To allow for a large increase in batch size, add a conditional reschedule to prune_icache_sb() so that we don't hold the LRU spin lock for too long. This mirrors the behaviour of the __shrink_dcache_sb(), and allows us to increase the batch size without needing to worry about problems caused by long lock hold times. To ensure that filesystems using the per-sb shrinker callouts don't cause problems, document that the object freeing method must reschedule appropriately inside loops. Signed-off-by: Dave Chinner <dchinner@redhat.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2011-07-21superblock: add filesystem shrinker operationsDave Chinner1-12/+33
Now we have a per-superblock shrinker implementation, we can add a filesystem specific callout to it to allow filesystem internal caches to be shrunk by the superblock shrinker. Rather than perpetuate the multipurpose shrinker callback API (i.e. nr_to_scan == 0 meaning "tell me how many objects freeable in the cache), two operations will be added. The first will return the number of objects that are freeable, the second is the actual shrinker call. Signed-off-by: Dave Chinner <dchinner@redhat.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2011-07-21inode: remove iprune_semDave Chinner1-21/+0
Now that we have per-sb shrinkers with a lifecycle that is a subset of the superblock lifecycle and can reliably detect a filesystem being unmounted, there is not longer any race condition for the iprune_sem to protect against. Hence we can remove it. Signed-off-by: Dave Chinner <dchinner@redhat.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2011-07-21superblock: introduce per-sb cache shrinker infrastructureDave Chinner3-218/+71
With context based shrinkers, we can implement a per-superblock shrinker that shrinks the caches attached to the superblock. We currently have global shrinkers for the inode and dentry caches that split up into per-superblock operations via a coarse proportioning method that does not batch very well. The global shrinkers also have a dependency - dentries pin inodes - so we have to be very careful about how we register the global shrinkers so that the implicit call order is always correct. With a per-sb shrinker callout, we can encode this dependency directly into the per-sb shrinker, hence avoiding the need for strictly ordering shrinker registrations. We also have no need for any proportioning code for the shrinker subsystem already provides this functionality across all shrinkers. Allowing the shrinker to operate on a single superblock at a time means that we do less superblock list traversals and locking and reclaim should batch more effectively. This should result in less CPU overhead for reclaim and potentially faster reclaim of items from each filesystem. Signed-off-by: Dave Chinner <dchinner@redhat.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2011-07-21xfs: add size update tracepoint to IO completionDave Chinner2-4/+9
For improving insight into IO completion behaviour. Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Alex Elder <aelder@sgi.com>
2011-07-21xfs: convert AIL cursors to use struct list_headDave Chinner2-55/+28
The list of active AIL cursors uses a roll-your-own linked list with special casing for the AIL push cursor. Simplify this code by replacing the list with standard struct list_head lists, and use a separate list_head to track the active cursors. This allows us to treat the AIL push cursor as a generic cursor rather than as a special case, further simplifying the code. Further, fix the duplicate push cursor initialisation that the special case handling was hiding, and clean up all the comments around the active cursor list handling. Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Alex Elder <aelder@sgi.com>
2011-07-21xfs: remove confusing ail cursor wrapperDave Chinner1-31/+19
xfs_trans_ail_cursor_set() doesn't set the cursor to the current log item, it sets it to the next item. There is already a function for doing this - xfs_trans_ail_cursor_next() - and the _set function is simply a two line wrapper. Remove it and open code the setting of the cursor in the two locations that call it to remove the confusion. Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Alex Elder <aelder@sgi.com>
2011-07-21xfs: use a cursor for bulk AIL insertionDave Chinner3-28/+118
Delayed logging can insert tens of thousands of log items into the AIL at the same LSN. When the committing of log commit records occur, we can get insertions occurring at an LSN that is not at the end of the AIL. If there are thousands of items in the AIL on the tail LSN, each insertion has to walk the AIL to find the correct place to insert the new item into the AIL. This can consume large amounts of CPU time and block other operations from occurring while the traversals are in progress. To avoid this repeated walk, use a AIL cursor to record where we should be inserting the new items into the AIL without having to repeat the walk. The cursor infrastructure already provides this functionality for push walks, so is a simple extension of existing code. While this will not avoid the initial walk, it will avoid repeating it tens of thousands of times during a single checkpoint commit. This version includes logic improvements from Christoph Hellwig. Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Alex Elder <aelder@sgi.com>
2011-07-21xfs: failure mapping nfs fh to inode should return ESTALEJ. Bruce Fields1-2/+2
On xfs exports, nfsd is incorrectly returning ENOENT instead of ESTALE on attempts to use a filehandle of a deleted file (spotted with pynfs test PUTFH3). The ENOENT was coming from xfs_iget. (It's tempting to wonder whether we should just map all xfs_iget errors to ESTALE, but I don't believe so--xfs_iget can also return ENOMEM at least, which we wouldn't want mapped to ESTALE.) While we're at it, the other return of ENOENT in xfs_nfs_get_inode() also looks wrong. Signed-off-by: J. Bruce Fields <bfields@redhat.com> Signed-off-by: Alex Elder <aelder@sgi.com>
2011-07-21xfs: Remove the second parameter to xfs_sb_count()Chandra Seetharaman3-12/+7
Remove the second parameter to xfs_sb_count() since all callers of the function set them. Also, fix the header comment regarding it being called periodically. Signed-off-by: Chandra Seetharaman <sekharan@us.ibm.com> Signed-off-by: Alex Elder <aelder@sgi.com>
2011-07-20superblock: move pin_sb_for_writeback() to fs/super.cDave Chinner3-27/+35
The per-sb shrinker has the same requirement as the writeback threads of ensuring that the superblock is usable and pinned for the time it takes to run the work. Both need to take a passive reference to the sb, take a read lock on the s_umount lock and then only continue if an unmount is not in progress. pin_sb_for_writeback() does this exactly, so move it to fs/super.c and rename it to grab_super_passive() and exporting it via fs/internal.h for all the VFS code to be able to use. Signed-off-by: Dave Chinner <dchinner@redhat.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2011-07-20inode: move to per-sb LRU locksDave Chinner2-14/+14
With the inode LRUs moving to per-sb structures, there is no longer a need for a global inode_lru_lock. The locking can be made more fine-grained by moving to a per-sb LRU lock, isolating the LRU operations of different filesytsems completely from each other. Signed-off-by: Dave Chinner <dchinner@redhat.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2011-07-20inode: Make unused inode LRU per superblockDave Chinner2-11/+81
The inode unused list is currently a global LRU. This does not match the other global filesystem cache - the dentry cache - which uses per-superblock LRU lists. Hence we have related filesystem object types using different LRU reclaimation schemes. To enable a per-superblock filesystem cache shrinker, both of these caches need to have per-sb unused object LRU lists. Hence this patch converts the global inode LRU to per-sb LRUs. The patch only does rudimentary per-sb propotioning in the shrinker infrastructure, as this gets removed when the per-sb shrinker callouts are introduced later on. Signed-off-by: Dave Chinner <dchinner@redhat.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2011-07-20inode: convert inode_stat.nr_unused to per-cpu countersDave Chinner1-5/+11
Before we split up the inode_lru_lock, the unused inode counter needs to be made independent of the global inode_lru_lock. Convert it to per-cpu counters to do this. Signed-off-by: Dave Chinner <dchinner@redhat.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2011-07-20make d_splice_alias(ERR_PTR(err), dentry) = ERR_PTR(err)Al Viro15-94/+39
... and simplify the living hell out of callers Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2011-07-20deuglify squashfs_lookup()Al Viro1-4/+1
d_splice_alias(NULL, dentry) is equivalent to d_add(dentry, NULL), NULL so no need for that if (inode) ... in there (or ERR_PTR(0), for that matter) Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2011-07-20nfsd4_list_rec_dir(): don't bother with reopening rec_fileAl Viro1-31/+21
just rewind it to the beginning before vfs_readdir() and be done with that... Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2011-07-20kill useless checks for sb->s_op == NULLAl Viro2-2/+1
never is... Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2011-07-20btrfs: kill magical embedded struct superblockAl Viro4-22/+29
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2011-07-20get rid of pointless checks for dentry->sb == NULLAl Viro1-1/+0
it never is... Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2011-07-20Make ->d_sb assign-once and always non-NULLAl Viro3-39/+47
New helper (non-exported, fs/internal.h-only): __d_alloc(sb, name). Allocates dentry, sets its ->d_sb to given superblock and sets ->d_op accordingly. Old d_alloc(NULL, name) callers are converted to that (all of them know what superblock they want). d_alloc() itself is left only for parent != NULl case; uses __d_alloc(), inserts result into the list of parent's children. Note that now ->d_sb is assign-once and never NULL *and* ->d_parent is never NULL either. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2011-07-20unexport kern_path_parent()Al Viro1-1/+0
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2011-07-20switch vfs_path_lookup() to struct pathAl Viro3-21/+20
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2011-07-20kill lookup_create()Al Viro1-36/+18
folded into the only caller (kern_path_create()) Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2011-07-20new helpers: kern_path_create/user_path_createAl Viro2-116/+87
combination of kern_path_parent() and lookup_create(). Does *not* expose struct nameidata to caller. Syscalls converted to that... Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2011-07-20kill LOOKUP_CONTINUEAl Viro1-8/+3
LOOKUP_PARENT is equivalent to it now Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2011-07-20nfs: LOOKUP_{OPEN,CREATE,EXCL} is set only on the last stepAl Viro1-4/+2
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2011-07-20cifs_lookup(): LOOKUP_OPEN is set only on the last componentAl Viro1-1/+1
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2011-07-20ceph: LOOKUP_OPEN is set only when it's the last componentAl Viro1-1/+0
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2011-07-20jfs_ci_revalidate() is safe from RCU modeAl Viro1-2/+0
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2011-07-20LOOKUP_CREATE and LOOKUP_RENAME_TARGET can be set only on the last stepAl Viro3-12/+6
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2011-07-20no need to check for LOOKUP_OPEN in ->create() instancesAl Viro5-10/+10
... it will be set in nd->flag for all cases with non-NULL nd (i.e. when called from do_last()). Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2011-07-20don't pass nameidata to vfs_create() from ecryptfs_create()Al Viro1-28/+5
Instead of playing with removal of LOOKUP_OPEN, mangling (and restoring) nd->path, just pass NULL to vfs_create(). The whole point of what's being done there is to suppress any attempts to open file by underlying fs, which is what nd == NULL indicates. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2011-07-20don't transliterate lower bits of ->intent.open.flags to FMODE_...Al Viro6-30/+23
->create() instances are much happier that way... Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2011-07-20Don't pass nameidata when calling vfs_create() from mknod()Al Viro1-1/+1
All instances can cope with that now (and ceph one actually starts working properly). Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2011-07-20fix mknod() on nfs4 (hopefully)Al Viro1-12/+12
a) check the right flags in ->create() (LOOKUP_OPEN, not LOOKUP_CREATE) b) default (!LOOKUP_OPEN) open_flags is O_CREAT|O_EXCL|FMODE_READ, not 0 c) lookup_instantiate_filp() should be done only with LOOKUP_OPEN; otherwise we need to issue CLOSE, lest we leak stateid on server. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2011-07-20nameidata_to_nfs_open_context() doesn't need nameidata, actually...Al Viro1-6/+7
just open flags; switched to passing just those and renamed to create_nfs_open_context() Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2011-07-20nfs_open_context doesn't need struct path eitherAl Viro7-42/+40
just dentry, please... Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2011-07-20nfs4_opendata doesn't need struct path eitherAl Viro1-23/+22
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2011-07-20nfs4_closedata doesn't need to mess with struct pathAl Viro3-22/+21
instead of path_get()/path_put(), we can just use nfs_sb_{,de}active() to pin the superblock down. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2011-07-20cifs: fix the type of cifs_demultiplex_thread()Al Viro1-2/+3
... and get rid of a bogus typecast, while we are at it; it's not just that we want a function returning int and not void, but cast to pointer to function taking void * and returning void would be (void (*)(void *)) and not (void *)(void *), TYVM... Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2011-07-20ecryptfs_inode_permission() doesn't need to bail out on RCUAl Viro1-2/+0
... now that inode_permission() can take MAY_NOT_BLOCK and handle it properly. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>