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| author | Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> | 2009-09-09 22:36:03 -0400 |
|---|---|---|
| committer | Theodore Ts'o <tytso@mit.edu> | 2009-09-09 22:36:03 -0400 |
| commit | a827eaffff07c7d58a4cb32158cbeb4849f4e33a (patch) | |
| tree | 6167caf1619f0d9555fd67a2facbf2351a0a7905 | |
| parent | 44fc48f7048ab9657b524938a832fec4e0acea98 (diff) | |
| download | linux-stable-a827eaffff07c7d58a4cb32158cbeb4849f4e33a.tar.gz linux-stable-a827eaffff07c7d58a4cb32158cbeb4849f4e33a.tar.bz2 linux-stable-a827eaffff07c7d58a4cb32158cbeb4849f4e33a.zip | |
ext4: Take page lock before looking at attached buffer_heads flags
In order to check whether the buffer_heads are mapped we need to hold
page lock. Otherwise a reclaim can cleanup the attached buffer_heads.
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
| -rw-r--r-- | fs/ext4/inode.c | 13 |
1 files changed, 11 insertions, 2 deletions
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c index 17802a96af9f..5c0d17066f4a 100644 --- a/fs/ext4/inode.c +++ b/fs/ext4/inode.c @@ -5286,12 +5286,21 @@ int ext4_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf) else len = PAGE_CACHE_SIZE; + lock_page(page); + /* + * return if we have all the buffers mapped. This avoid + * the need to call write_begin/write_end which does a + * journal_start/journal_stop which can block and take + * long time + */ if (page_has_buffers(page)) { - /* return if we have all the buffers mapped */ if (!walk_page_buffers(NULL, page_buffers(page), 0, len, NULL, - ext4_bh_unmapped)) + ext4_bh_unmapped)) { + unlock_page(page); goto out_unlock; + } } + unlock_page(page); /* * OK, we need to fill the hole... Do write_begin write_end * to do block allocation/reservation.We are not holding |