android_kernel_xiaomi_sm8350/fs/ext3
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
..
acl.c
acl.h
balloc.c CRED: Wrap task credential accesses in the Ext3 filesystem 2008-11-14 10:38:51 +11:00
bitmap.c
dir.c ext3: Fix duplicate entries returned from getdents() system call 2008-10-25 22:37:44 -04:00
ext3_jbd.c
file.c generic block based fiemap implementation 2008-10-03 17:32:43 -04:00
fsync.c
hash.c
ialloc.c nfsd race fixes: ext3 2008-12-31 18:07:44 -05:00
inode.c fs: symlink write_begin allocation context fix 2009-01-04 13:33:20 -08:00
ioctl.c ext3: add checks for errors from jbd 2008-10-23 08:55:01 -07:00
Kconfig fs/Kconfig: move ext2, ext3, ext4, JBD, JBD2 out 2008-10-20 11:43:59 -07:00
Makefile
namei.c fs: symlink write_begin allocation context fix 2009-01-04 13:33:20 -08:00
namei.h
resize.c ext3: don't try to resize if there are no reserved gdt blocks left 2008-10-20 08:52:37 -07:00
super.c ext3: Clean up outdated and incorrect comment for ext3_write_super() 2008-11-12 17:17:17 -08:00
symlink.c
xattr_security.c
xattr_trusted.c
xattr_user.c
xattr.c
xattr.h