From: Jan Kara <jack@xxxxxxx> 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@xxxxxxx> Signed-off-by: "Theodore Ts'o" <tytso@xxxxxxx> (cherry picked from commit ebd3610b110bbb18ea6f9f2aeed1e1068c537227) --- fs/ext4/inode.c | 9 ++++++++- 1 files changed, 8 insertions(+), 1 deletions(-) diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c index c794e61..b7f20b0 100644 --- a/fs/ext4/inode.c +++ b/fs/ext4/inode.c @@ -1347,6 +1347,10 @@ 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); @@ -1356,7 +1360,7 @@ 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), @@ -2603,6 +2607,9 @@ 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) { -- 1.5.6.3 -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
