projects / people / pmueller / ipfire-2.x.git / blame
| Commit | Line | Data |
|---|---|---|
| 2cb7cef9 BS |
1 | From: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> |
| 2 | Date: Thu, 14 May 2009 21:05:39 +0000 (-0400) | |
| 3 | Subject: ext4: Clear the unwritten buffer_head flag after the extent is initialized | |
| 4 | Patch-mainline: 2.6.30-rc6 | |
| 5 | Git-commit: 2a8964d63d50dd2d65d71d342bc7fb6ef4117614 | |
| 6 | References: bnc#503161 | |
| 7 | ||
| 8 | ext4: Clear the unwritten buffer_head flag after the extent is initialized | |
| 9 | ||
| 10 | The BH_Unwritten flag indicates that the buffer is allocated on disk | |
| 11 | but has not been written; that is, the disk was part of a persistent | |
| 12 | preallocation area. That flag should only be set when a get_blocks() | |
| 13 | function is looking up a inode's logical to physical block mapping. | |
| 14 | ||
| 15 | When ext4_get_blocks_wrap() is called with create=1, the uninitialized | |
| 16 | extent is converted into an initialized one, so the BH_Unwritten flag | |
| 17 | is no longer appropriate. Hence, we need to make sure the | |
| 18 | BH_Unwritten is not left set, since the combination of BH_Mapped and | |
| 19 | BH_Unwritten is not allowed; among other things, it will result ext4's | |
| 20 | get_block() to be called over and over again during the write_begin | |
| 21 | phase of write(2). | |
| 22 | ||
| 23 | Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> | |
| 24 | Signed-off-by: "Theodore Ts'o" <tytso@mit.edu> | |
| 25 | Acked-by: Jeff Mahoney <jeffm@suse.com> | |
| 26 | --- | |
| 27 | ||
| 28 | fs/ext4/inode.c | 13 +++++++++++++ | |
| 29 | 1 file changed, 13 insertions(+) | |
| 30 | ||
| 31 | --- a/fs/ext4/inode.c | |
| 32 | +++ b/fs/ext4/inode.c | |
| 33 | @@ -1058,6 +1058,7 @@ int ext4_get_blocks_wrap(handle_t *handl | |
| 34 | int retval; | |
| 35 | ||
| 36 | clear_buffer_mapped(bh); | |
| 37 | + clear_buffer_unwritten(bh); | |
| 38 | ||
| 39 | /* | |
| 40 | * Try to see if we can get the block without requesting | |
| 41 | @@ -1088,6 +1089,18 @@ int ext4_get_blocks_wrap(handle_t *handl | |
| 42 | return retval; | |
| 43 | ||
| 44 | /* | |
| 45 | + * When we call get_blocks without the create flag, the | |
| 46 | + * BH_Unwritten flag could have gotten set if the blocks | |
| 47 | + * requested were part of a uninitialized extent. We need to | |
| 48 | + * clear this flag now that we are committed to convert all or | |
| 49 | + * part of the uninitialized extent to be an initialized | |
| 50 | + * extent. This is because we need to avoid the combination | |
| 51 | + * of BH_Unwritten and BH_Mapped flags being simultaneously | |
| 52 | + * set on the buffer_head. | |
| 53 | + */ | |
| 54 | + clear_buffer_unwritten(bh); | |
| 55 | + | |
| 56 | + /* | |
| 57 | * New blocks allocate and/or writing to uninitialized extent | |
| 58 | * will possibly result in updating i_data, so we take | |
| 59 | * the write lock of i_data_sem, and call get_blocks() |