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2011-07-20fs: always maintain i_dio_countChristoph Hellwig
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>
2011-07-20fs: move inode_dio_wait calls into ->setattrChristoph Hellwig
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>
2011-07-20fs: kill i_alloc_semChristoph Hellwig
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>
2011-07-20fs: simplify handling of zero sized reads in __blockdev_direct_IOChristoph Hellwig
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>
2011-07-20ext4: Rewrite ext4_page_mkwrite() to use generic helpersJan Kara
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>
2011-07-20fat: remove i_alloc_sem abuseChristoph Hellwig
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>
2011-07-20VFS: Fixup kerneldoc for generic_permission()Tobias Klauser
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>
2011-07-20xfs: make use of new shrinker callout for the inode cacheDave Chinner
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>
2011-07-20vfs: increase shrinker batch sizeDave Chinner
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>
2011-07-20superblock: add filesystem shrinker operationsDave Chinner
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>
2011-07-20inode: remove iprune_semDave Chinner
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>
2011-07-20superblock: introduce per-sb cache shrinker infrastructureDave Chinner
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>
2011-07-20superblock: move pin_sb_for_writeback() to fs/super.cDave Chinner
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 Chinner
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 Chinner
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 Chinner
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 Viro
... and simplify the living hell out of callers Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2011-07-20deuglify squashfs_lookup()Al Viro
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 Viro
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 Viro
never is... Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2011-07-20btrfs: kill magical embedded struct superblockAl Viro
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2011-07-20get rid of pointless checks for dentry->sb == NULLAl Viro
it never is... Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2011-07-20Make ->d_sb assign-once and always non-NULLAl Viro
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 Viro
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2011-07-20switch vfs_path_lookup() to struct pathAl Viro
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2011-07-20kill lookup_create()Al Viro
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 Viro
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 Viro
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 Viro
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2011-07-20cifs_lookup(): LOOKUP_OPEN is set only on the last componentAl Viro
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2011-07-20ceph: LOOKUP_OPEN is set only when it's the last componentAl Viro
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2011-07-20jfs_ci_revalidate() is safe from RCU modeAl Viro
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 Viro
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2011-07-20no need to check for LOOKUP_OPEN in ->create() instancesAl Viro
... 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 Viro
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 Viro
->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 Viro
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 Viro
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 Viro
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 Viro
just dentry, please... Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2011-07-20nfs4_opendata doesn't need struct path eitherAl Viro
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2011-07-20nfs4_closedata doesn't need to mess with struct pathAl Viro
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 Viro
... 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 Viro
... now that inode_permission() can take MAY_NOT_BLOCK and handle it properly. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2011-07-20merge do_revalidate() into its only callerAl Viro
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2011-07-20no reason to keep exec_permission() separate nowAl Viro
cache footprint alone makes it a bad idea... Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2011-07-20massage generic_permission() to treat directories on a separate pathAl Viro
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2011-07-20->permission() sanitizing: don't pass flags to exec_permission()Al Viro
pass mask instead; kill security_inode_exec_permission() since we can use security_inode_permission() instead. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2011-07-20->permission() sanitizing: don't pass flags to ->permission()Al Viro
not used by the instances anymore. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2011-07-20->permission() sanitizing: don't pass flags to generic_permission()Al Viro
redundant; all callers get it duplicated in mask & MAY_NOT_BLOCK and none of them removes that bit. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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