diff options
| author | Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> | 2009-06-02 08:09:35 -0400 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@suse.de> | 2009-06-11 20:01:59 -0700 |
| commit | ef3740934e85572dce2e20cecea3341fd43647e0 (patch) | |
| tree | eb5fd1e19b3036f605917956b6520960bc2e4b38 /fs/ext4 | |
| parent | f0e70fb39944b1345203ab72d4c6117da6bf072a (diff) | |
ext4: Clear the unwritten buffer_head flag after the extent is initialized
(cherry picked from commit 2a8964d63d50dd2d65d71d342bc7fb6ef4117614)
The BH_Unwritten flag indicates that the buffer is allocated on disk
but has not been written; that is, the disk was part of a persistent
preallocation area. That flag should only be set when a get_blocks()
function is looking up a inode's logical to physical block mapping.
When ext4_get_blocks_wrap() is called with create=1, the uninitialized
extent is converted into an initialized one, so the BH_Unwritten flag
is no longer appropriate. Hence, we need to make sure the
BH_Unwritten is not left set, since the combination of BH_Mapped and
BH_Unwritten is not allowed; among other things, it will result ext4's
get_block() to be called over and over again during the write_begin
phase of write(2).
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Diffstat (limited to 'fs/ext4')
| -rw-r--r-- | fs/ext4/inode.c | 13 |
1 files changed, 13 insertions, 0 deletions
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c index 40519bddce0..aeebfc25516 100644 --- a/fs/ext4/inode.c +++ b/fs/ext4/inode.c @@ -1085,6 +1085,7 @@ int ext4_get_blocks_wrap(handle_t *handle, struct inode *inode, sector_t block, int retval; clear_buffer_mapped(bh); + clear_buffer_unwritten(bh); /* * Try to see if we can get the block without requesting @@ -1115,6 +1116,18 @@ int ext4_get_blocks_wrap(handle_t *handle, struct inode *inode, sector_t block, return retval; /* + * When we call get_blocks without the create flag, the + * BH_Unwritten flag could have gotten set if the blocks + * requested were part of a uninitialized extent. We need to + * clear this flag now that we are committed to convert all or + * part of the uninitialized extent to be an initialized + * extent. This is because we need to avoid the combination + * of BH_Unwritten and BH_Mapped flags being simultaneously + * set on the buffer_head. + */ + clear_buffer_unwritten(bh); + + /* * New blocks allocate and/or writing to uninitialized extent * will possibly result in updating i_data, so we take * the write lock of i_data_sem, and call get_blocks() |