linux/mm
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
..
allocpercpu.c mm/allocpercpu.c: make 4 functions static 2008-07-26 12:00:12 -07:00
backing-dev.c mm/backing-dev.c: remove recently-added WARN_ON() 2008-12-10 08:01:52 -08:00
bootmem.c misc: replace __FUNCTION__ with __func__ 2008-10-16 11:21:30 -07:00
bounce.c bounce: don't rely on a zeroed bio_vec list 2008-12-29 08:29:52 +01:00
dmapool.c
fadvise.c Remove Andrew Morton's old email accounts 2008-10-16 11:21:32 -07:00
failslab.c SLUB: failslab support 2008-12-29 11:27:46 +02:00
filemap_xip.c mm: xip/ext2 fix block allocation race 2008-08-20 15:40:32 -07:00
filemap.c fs: symlink write_begin allocation context fix 2009-01-04 13:33:20 -08:00
fremap.c mmap: handle mlocked pages during map, remap, unmap 2008-10-20 08:52:31 -07:00
highmem.c x86, pat: avoid highmem cache attribute aliasing 2008-08-15 17:22:57 +02:00
hugetlb.c hugetlb: make unmap_ref_private multi-size-aware 2008-11-12 17:17:16 -08:00
internal.h hugetlb: pull gigantic page initialisation out of the default path 2008-11-06 15:41:18 -08:00
Kconfig Unevictable LRU Infrastructure 2008-10-20 08:50:26 -07:00
maccess.c
madvise.c madvise: update function comment of madvise_dontneed 2008-07-30 09:41:45 -07:00
Makefile SLUB: failslab support 2008-12-29 11:27:46 +02:00
memcontrol.c memcg: fix page_cgroup allocation 2008-10-23 08:55:02 -07:00
memory_hotplug.c meminit section warnings 2008-11-30 10:03:35 -08:00
memory.c Merge branch 'core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2008-12-30 16:10:19 -08:00
mempolicy.c Merge branch 'master' into next 2008-11-14 11:29:12 +11:00
mempool.c
migrate.c Merge branch 'next' into for-linus 2008-12-25 11:40:09 +11:00
mincore.c
mlock.c x86, bts: memory accounting 2008-12-20 09:15:47 +01:00
mm_init.c mm: mminit_loglevel cannot be __meminitdata anymore 2008-08-20 15:40:30 -07:00
mmap.c parisc: fix find_extend_vma() breakage 2008-11-12 10:37:48 -08:00
mmu_notifier.c mmu-notifiers: core 2008-07-28 16:30:21 -07:00
mmzone.c mm: mark the correct zone as full when scanning zonelists 2008-09-13 14:41:52 -07:00
mprotect.c mmu-notifiers: core 2008-07-28 16:30:21 -07:00
mremap.c mmap: handle mlocked pages during map, remap, unmap 2008-10-20 08:52:31 -07:00
msync.c
nommu.c nfsd: fix vm overcommit crash 2008-10-30 11:38:47 -07:00
oom_kill.c Merge branch 'master' into next 2008-11-14 11:29:12 +11:00
page_alloc.c cpusets: update mems allowed in page allocator 2008-11-12 17:17:16 -08:00
page_cgroup.c page_cgroup should ignore empty nodes 2008-12-10 08:01:53 -08:00
page_io.c
page_isolation.c memory hotplug: fix page_zone() calculation in test_pages_isolated() 2008-11-06 15:41:19 -08:00
page-writeback.c vmscan: split LRU lists into anon & file sets 2008-10-20 08:50:25 -07:00
pagewalk.c
pdflush.c cpumask: convert mm/ 2009-01-01 10:12:29 +10:30
prio_tree.c
quicklist.c mm: size of quicklists shouldn't be proportional to the number of CPUs 2008-09-02 19:21:38 -07:00
readahead.c vmscan: split LRU lists into anon & file sets 2008-10-20 08:50:25 -07:00
rmap.c make mm/rmap.c:anon_vma_cachep static 2008-10-20 08:52:40 -07:00
shmem_acl.c [PATCH] sanitize ->permission() prototype 2008-07-26 20:53:14 -04:00
shmem.c CRED: Wrap task credential accesses in the core kernel 2008-11-14 10:39:12 +11:00
slab.c cpumask: convert mm/ 2009-01-01 10:12:29 +10:30
slob.c slob: do not pass the SLAB flags as GFP in kmem_cache_create() 2008-12-15 16:27:06 -08:00
slub.c cpumask: convert mm/ 2009-01-01 10:12:29 +10:30
sparse-vmemmap.c vmemmap: warn about page_structs with remote distance 2008-11-06 15:41:19 -08:00
sparse.c meminit section warnings 2008-11-30 10:03:35 -08:00
swap_state.c mm: pagecache insertion fewer atomics 2008-10-20 08:52:31 -07:00
swap.c mm: remove UP version of lru_add_drain_all() 2008-12-10 08:01:53 -08:00
swapfile.c x86: consolidate __swp_XXX() macros 2008-12-16 18:34:51 +01:00
thrash.c
tiny-shmem.c Export tiny shmem_file_setup for DRM-GEM 2008-10-20 16:17:42 -07:00
truncate.c mmap: handle mlocked pages during map, remap, unmap 2008-10-20 08:52:31 -07:00
util.c mm: Make generic weak get_user_pages_fast and EXPORT_GPL it 2008-08-12 17:52:53 +10:00
vmalloc.c vmalloc.c: fix flushing in vmap_page_range() 2009-01-04 13:33:20 -08:00
vmscan.c cpumask: convert mm/ 2009-01-01 10:12:29 +10:30
vmstat.c cpumask: convert mm/ 2009-01-01 10:12:29 +10:30