diff options
| author | Nick Piggin <npiggin@suse.de> | 2009-01-04 12:00:53 -0800 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@suse.de> | 2009-01-18 10:43:46 -0800 |
| commit | 4f093b80fa8facbd22fa36c00242e2fffa36e12f (patch) | |
| tree | cb989e573174d1f9b77a27fbb4d1028b7e453d45 /fs/ext4 | |
| parent | d7ffe47eece22194f75f78fa488e1b4cd16980bf (diff) | |
fs: symlink write_begin allocation context fix
commit 54566b2c1594c2326a645a3551f9d989f7ba3c5e upstream.
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>
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>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Diffstat (limited to 'fs/ext4')
| -rw-r--r-- | fs/ext4/inode.c | 4 | ||||
| -rw-r--r-- | fs/ext4/namei.c | 3 |
2 files changed, 3 insertions, 4 deletions
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c index be21a5ae33cb..8e46b19e913f 100644 --- a/fs/ext4/inode.c +++ b/fs/ext4/inode.c @@ -1345,7 +1345,7 @@ retry: goto out; } - page = __grab_cache_page(mapping, index); + page = grab_cache_page_write_begin(mapping, index, flags); if (!page) { ext4_journal_stop(handle); ret = -ENOMEM; @@ -2549,7 +2549,7 @@ retry: goto out; } - page = __grab_cache_page(mapping, index); + page = grab_cache_page_write_begin(mapping, index, flags); if (!page) { ext4_journal_stop(handle); ret = -ENOMEM; diff --git a/fs/ext4/namei.c b/fs/ext4/namei.c index 63adcb792988..92c839762218 100644 --- a/fs/ext4/namei.c +++ b/fs/ext4/namei.c @@ -2208,8 +2208,7 @@ retry: * We have a transaction open. All is sweetness. It also sets * i_size in generic_commit_write(). */ - err = __page_symlink(inode, symname, l, - mapping_gfp_mask(inode->i_mapping) & ~__GFP_FS); + err = __page_symlink(inode, symname, l, 1); if (err) { clear_nlink(inode); ext4_mark_inode_dirty(handle, inode); |