* [patch 13/19] vfs: fix possible deadlock in ext2, ext3, ext4 when using xattrs
@ 2008-04-15 21:34 akpm
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From: akpm @ 2008-04-15 21:34 UTC (permalink / raw
To: torvalds; +Cc: akpm, jack, davej, linux-ext4
From: Jan Kara <jack@suse.cz>
mb_cache_entry_alloc() was allocating cache entries with GFP_KERNEL. But
filesystems are calling this function while holding xattr_sem so possible
recursion into the fs violates locking ordering of xattr_sem and transaction
start / i_mutex for ext2-4. Change mb_cache_entry_alloc() so that filesystems
can specify desired gfp mask and use GFP_NOFS from all of them.
Signed-off-by: Jan Kara <jack@suse.cz>
Reported-by: Dave Jones <davej@redhat.com>
Cc: <linux-ext4@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---
fs/ext2/xattr.c | 2 +-
fs/ext3/xattr.c | 2 +-
fs/ext4/xattr.c | 2 +-
fs/mbcache.c | 4 ++--
include/linux/mbcache.h | 2 +-
5 files changed, 6 insertions(+), 6 deletions(-)
diff -puN fs/ext2/xattr.c~vfs-fix-possible-deadlock-in-ext2-ext3-ext4-when-using-xattrs fs/ext2/xattr.c
--- a/fs/ext2/xattr.c~vfs-fix-possible-deadlock-in-ext2-ext3-ext4-when-using-xattrs
+++ a/fs/ext2/xattr.c
@@ -835,7 +835,7 @@ ext2_xattr_cache_insert(struct buffer_he
struct mb_cache_entry *ce;
int error;
- ce = mb_cache_entry_alloc(ext2_xattr_cache);
+ ce = mb_cache_entry_alloc(ext2_xattr_cache, GFP_NOFS);
if (!ce)
return -ENOMEM;
error = mb_cache_entry_insert(ce, bh->b_bdev, bh->b_blocknr, &hash);
diff -puN fs/ext3/xattr.c~vfs-fix-possible-deadlock-in-ext2-ext3-ext4-when-using-xattrs fs/ext3/xattr.c
--- a/fs/ext3/xattr.c~vfs-fix-possible-deadlock-in-ext2-ext3-ext4-when-using-xattrs
+++ a/fs/ext3/xattr.c
@@ -1126,7 +1126,7 @@ ext3_xattr_cache_insert(struct buffer_he
struct mb_cache_entry *ce;
int error;
- ce = mb_cache_entry_alloc(ext3_xattr_cache);
+ ce = mb_cache_entry_alloc(ext3_xattr_cache, GFP_NOFS);
if (!ce) {
ea_bdebug(bh, "out of memory");
return;
diff -puN fs/ext4/xattr.c~vfs-fix-possible-deadlock-in-ext2-ext3-ext4-when-using-xattrs fs/ext4/xattr.c
--- a/fs/ext4/xattr.c~vfs-fix-possible-deadlock-in-ext2-ext3-ext4-when-using-xattrs
+++ a/fs/ext4/xattr.c
@@ -1386,7 +1386,7 @@ ext4_xattr_cache_insert(struct buffer_he
struct mb_cache_entry *ce;
int error;
- ce = mb_cache_entry_alloc(ext4_xattr_cache);
+ ce = mb_cache_entry_alloc(ext4_xattr_cache, GFP_NOFS);
if (!ce) {
ea_bdebug(bh, "out of memory");
return;
diff -puN fs/mbcache.c~vfs-fix-possible-deadlock-in-ext2-ext3-ext4-when-using-xattrs fs/mbcache.c
--- a/fs/mbcache.c~vfs-fix-possible-deadlock-in-ext2-ext3-ext4-when-using-xattrs
+++ a/fs/mbcache.c
@@ -399,11 +399,11 @@ mb_cache_destroy(struct mb_cache *cache)
* if no more memory was available.
*/
struct mb_cache_entry *
-mb_cache_entry_alloc(struct mb_cache *cache)
+mb_cache_entry_alloc(struct mb_cache *cache, gfp_t gfp_flags)
{
struct mb_cache_entry *ce;
- ce = kmem_cache_alloc(cache->c_entry_cache, GFP_KERNEL);
+ ce = kmem_cache_alloc(cache->c_entry_cache, gfp_flags);
if (ce) {
atomic_inc(&cache->c_entry_count);
INIT_LIST_HEAD(&ce->e_lru_list);
diff -puN include/linux/mbcache.h~vfs-fix-possible-deadlock-in-ext2-ext3-ext4-when-using-xattrs include/linux/mbcache.h
--- a/include/linux/mbcache.h~vfs-fix-possible-deadlock-in-ext2-ext3-ext4-when-using-xattrs
+++ a/include/linux/mbcache.h
@@ -34,7 +34,7 @@ void mb_cache_destroy(struct mb_cache *)
/* Functions on cache entries */
-struct mb_cache_entry *mb_cache_entry_alloc(struct mb_cache *);
+struct mb_cache_entry *mb_cache_entry_alloc(struct mb_cache *, gfp_t);
int mb_cache_entry_insert(struct mb_cache_entry *, struct block_device *,
sector_t, unsigned int[]);
void mb_cache_entry_release(struct mb_cache_entry *);
_
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2008-04-15 21:34 [patch 13/19] vfs: fix possible deadlock in ext2, ext3, ext4 when using xattrs akpm
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