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| author | Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> | 2009-05-14 17:05:39 -0400 |
|---|---|---|
| committer | Theodore Ts'o <tytso@mit.edu> | 2009-05-14 17:05:39 -0400 |
| commit | 2a8964d63d50dd2d65d71d342bc7fb6ef4117614 (patch) | |
| tree | 7dd80d63afd9adab61ba0695ac3e0c95485dc2ed /fs | |
| parent | 33b9817e2ae097c7b8d256e3510ac6c54fc6d9d0 (diff) | |
| download | op-kernel-dev-2a8964d63d50dd2d65d71d342bc7fb6ef4117614.zip op-kernel-dev-2a8964d63d50dd2d65d71d342bc7fb6ef4117614.tar.gz | |
ext4: Clear the unwritten buffer_head flag after the extent is initialized
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>
Diffstat (limited to 'fs')
| -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 0ac31a0..2a9ffd5 100644 --- a/fs/ext4/inode.c +++ b/fs/ext4/inode.c @@ -1149,6 +1149,7 @@ 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 @@ -1179,6 +1180,18 @@ 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() |
