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author | Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> | 2008-01-29 04:58:29 (GMT) |
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committer | Theodore Ts'o <tytso@mit.edu> | 2008-01-29 04:58:29 (GMT) |
commit | 4df3d265bf8f3762e1d77f554ee279c39dedb020 (patch) | |
tree | 35d455ac6592750450d9173125b1e5b9b5efe819 /fs/ext4/inode.c | |
parent | 0e855ac8b103ef579052936b59fe7c599ac422a4 (diff) | |
download | linux-fsl-qoriq-4df3d265bf8f3762e1d77f554ee279c39dedb020.tar.xz |
ext4: Take read lock during overwrite case.
When we are overwriting a file and not actually allocating new file system
blocks we need to take only the read lock on i_data_sem.
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Diffstat (limited to 'fs/ext4/inode.c')
-rw-r--r-- | fs/ext4/inode.c | 32 |
1 files changed, 24 insertions, 8 deletions
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c index a7eb8bb..89cd353 100644 --- a/fs/ext4/inode.c +++ b/fs/ext4/inode.c @@ -901,11 +901,31 @@ int ext4_get_blocks_wrap(handle_t *handle, struct inode *inode, sector_t block, int create, int extend_disksize) { int retval; - if (create) { - down_write((&EXT4_I(inode)->i_data_sem)); + /* + * Try to see if we can get the block without requesting + * for new file system block. + */ + down_read((&EXT4_I(inode)->i_data_sem)); + if (EXT4_I(inode)->i_flags & EXT4_EXTENTS_FL) { + retval = ext4_ext_get_blocks(handle, inode, block, max_blocks, + bh, 0, 0); } else { - down_read((&EXT4_I(inode)->i_data_sem)); + retval = ext4_get_blocks_handle(handle, + inode, block, max_blocks, bh, 0, 0); } + up_read((&EXT4_I(inode)->i_data_sem)); + if (!create || (retval > 0)) + return retval; + + /* + * We need to allocate new blocks which will result + * in i_data update + */ + down_write((&EXT4_I(inode)->i_data_sem)); + /* + * We need to check for EXT4 here because migrate + * could have changed the inode type in between + */ if (EXT4_I(inode)->i_flags & EXT4_EXTENTS_FL) { retval = ext4_ext_get_blocks(handle, inode, block, max_blocks, bh, create, extend_disksize); @@ -913,11 +933,7 @@ int ext4_get_blocks_wrap(handle_t *handle, struct inode *inode, sector_t block, retval = ext4_get_blocks_handle(handle, inode, block, max_blocks, bh, create, extend_disksize); } - if (create) { - up_write((&EXT4_I(inode)->i_data_sem)); - } else { - up_read((&EXT4_I(inode)->i_data_sem)); - } + up_write((&EXT4_I(inode)->i_data_sem)); return retval; } |