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authorJan Kara <jack@suse.cz>2009-03-05 02:34:07 -0500
committerGreg Kroah-Hartman <gregkh@suse.de>2009-03-16 17:53:06 -0700
commit5b9c305d22fb08a6b62f407e187f8f2a5b91c54f (patch)
tree45a5796c7edd50cc725c39a9d0a94fda49dda33f
parent3d2f446880e9c0cd89aed563dae0d34d379a0826 (diff)
ext4: Fix deadlock in ext4_write_begin() and ext4_da_write_begin()
(cherry picked from commit ebd3610b110bbb18ea6f9f2aeed1e1068c537227) Functions ext4_write_begin() and ext4_da_write_begin() call grab_cache_page_write_begin() without AOP_FLAG_NOFS. Thus it can happen that page reclaim is triggered in that function and it recurses back into the filesystem (or some other filesystem). But this can lead to various problems as a transaction is already started at that point. Add the necessary flag. http://bugzilla.kernel.org/show_bug.cgi?id=11688 Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: "Theodore Ts'o" <tytso@mit.edu> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
-rw-r--r--fs/ext4/inode.c9
1 files changed, 8 insertions, 1 deletions
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index 7b063d445389..b233ade46cfd 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -1372,6 +1372,10 @@ retry:
goto out;
}
+ /* We cannot recurse into the filesystem as the transaction is already
+ * started */
+ flags |= AOP_FLAG_NOFS;
+
page = grab_cache_page_write_begin(mapping, index, flags);
if (!page) {
ext4_journal_stop(handle);
@@ -1381,7 +1385,7 @@ retry:
*pagep = page;
ret = block_write_begin(file, mapping, pos, len, flags, pagep, fsdata,
- ext4_get_block);
+ ext4_get_block);
if (!ret && ext4_should_journal_data(inode)) {
ret = walk_page_buffers(handle, page_buffers(page),
@@ -2465,6 +2469,9 @@ retry:
ret = PTR_ERR(handle);
goto out;
}
+ /* We cannot recurse into the filesystem as the transaction is already
+ * started */
+ flags |= AOP_FLAG_NOFS;
page = grab_cache_page_write_begin(mapping, index, flags);
if (!page) {