linux/fs/afs
Nick Piggin 54566b2c15 fs: symlink write_begin allocation context fix
With the write_begin/write_end aops, page_symlink was broken because it
could no longer pass a GFP_NOFS type mask into the point where the
allocations happened.  They are done in write_begin, which would always
assume that the filesystem can be entered from reclaim.  This bug could
cause filesystem deadlocks.

The funny thing with having a gfp_t mask there is that it doesn't really
allow the caller to arbitrarily tinker with the context in which it can be
called.  It couldn't ever be GFP_ATOMIC, for example, because it needs to
take the page lock.  The only thing any callers care about is __GFP_FS
anyway, so turn that into a single flag.

Add a new flag for write_begin, AOP_FLAG_NOFS.  Filesystems can now act on
this flag in their write_begin function.  Change __grab_cache_page to
accept a nofs argument as well, to honour that flag (while we're there,
change the name to grab_cache_page_write_begin which is more instructive
and does away with random leading underscores).

This is really a more flexible way to go in the end anyway -- if a
filesystem happens to want any extra allocations aside from the pagecache
ones in ints write_begin function, it may now use GFP_KERNEL (rather than
GFP_NOFS) for common case allocations (eg.  ocfs2_alloc_write_ctxt, for a
random example).

[kosaki.motohiro@jp.fujitsu.com: fix ubifs]
[kosaki.motohiro@jp.fujitsu.com: fix fuse]
Signed-off-by: Nick Piggin <npiggin@suse.de>
Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: <stable@kernel.org>		[2.6.28.x]
Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
[ Cleaned up the calling convention: just pass in the AOP flags
  untouched to the grab_cache_page_write_begin() function.  That
  just simplifies everybody, and may even allow future expansion of the
  logic.   - Linus ]
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-01-04 13:33:20 -08:00
..
afs_cm.h afs: support the CB.ProbeUuid RPC op 2008-04-29 08:06:26 -07:00
afs_fs.h AFS: implement file locking 2007-07-16 09:05:43 -07:00
afs_vl.h [AF_RXRPC]: Make the in-kernel AFS filesystem use AF_RXRPC. 2007-04-26 15:55:03 -07:00
afs.h AFS: implement file locking 2007-07-16 09:05:43 -07:00
cache.c [AF_RXRPC]: Make the in-kernel AFS filesystem use AF_RXRPC. 2007-04-26 15:55:03 -07:00
cache.h [AFS]: Clean up the AFS sources 2007-04-26 15:49:28 -07:00
callback.c Fix various old email addresses for dwmw2 2008-06-06 11:29:10 -07:00
cell.c afs: use the shorter LIST_HEAD for brevity 2008-04-29 08:06:26 -07:00
cmservice.c afs: support the CB.ProbeUuid RPC op 2008-04-29 08:06:26 -07:00
dir.c [PATCH] fix ->llseek for more directories 2008-10-23 05:13:21 -04:00
file.c afs: convert to new aops 2008-10-16 11:21:48 -07:00
flock.c AFS: clean up explicit check for mandatory locks 2007-10-09 18:32:46 -04:00
fsclient.c AFS: implement file locking 2007-07-16 09:05:43 -07:00
inode.c Fix various old email addresses for dwmw2 2008-06-06 11:29:10 -07:00
internal.h afs: convert to new aops 2008-10-16 11:21:48 -07:00
main.c AFS: Do not describe debug parameters with their value 2008-04-16 07:43:48 -07:00
Makefile AFS: implement file locking 2007-07-16 09:05:43 -07:00
misc.c AFS: implement file locking 2007-07-16 09:05:43 -07:00
mntpt.c [PATCH] pass struct path * to do_add_mount() 2008-08-01 11:25:32 -04:00
netdevices.c [NET]: Make the device list and device lookups per namespace. 2007-10-10 16:49:10 -07:00
proc.c fs: replace NIPQUAD() 2008-10-31 00:56:28 -07:00
rxrpc.c fs/afs/: possible cleanups 2007-10-17 08:42:50 -07:00
security.c [PATCH] sanitize ->permission() prototype 2008-07-26 20:53:14 -04:00
server.c fs: replace NIPQUAD() 2008-10-31 00:56:28 -07:00
super.c vfs: Use const for kernel parser table 2008-10-13 10:10:37 -07:00
vlclient.c [AFS]: Add security support. 2007-04-26 15:57:07 -07:00
vlocation.c fs/afs/vlocation.c: fix off-by-one 2007-11-05 15:12:32 -08:00
vnode.c AFS: drop explicit extern 2007-07-16 09:05:43 -07:00
volume.c Detach sched.h from mm.h 2007-05-21 09:18:19 -07:00
write.c fs: symlink write_begin allocation context fix 2009-01-04 13:33:20 -08:00