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authorJan Kara <jack@suse.cz>2013-06-04 12:56:55 -0400
committerTheodore Ts'o <tytso@mit.edu>2013-06-04 12:56:55 -0400
commitfa55a0ed0386e1fcbb8a229a06a5c70477d0d6e5 (patch)
tree8b1abbd432fd799ff7d537851d758c0a7b1e26a8
parentf2d50a65c93cfe718742bc85dff55bf8f11967b6 (diff)
downloadop-kernel-dev-fa55a0ed0386e1fcbb8a229a06a5c70477d0d6e5.zip
op-kernel-dev-fa55a0ed0386e1fcbb8a229a06a5c70477d0d6e5.tar.gz
ext4: improve writepage credit estimate for files with indirect blocks
ext4_ind_trans_blocks() wrongly used 'chunk' argument to decide whether blocks mapped are logically contiguous. That is wrong since the argument informs whether the blocks are physically contiguous. As the blocks mapped are always logically contiguous and that's all ext4_ind_trans_blocks() cares about, just remove the 'chunk' argument. Reviewed-by: Zheng Liu <wenqing.lz@taobao.com> Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
-rw-r--r--fs/ext4/ext4.h2
-rw-r--r--fs/ext4/indirect.c27
-rw-r--r--fs/ext4/inode.c2
3 files changed, 11 insertions, 20 deletions
diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index 4667405..25e261d 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -2109,7 +2109,7 @@ extern ssize_t ext4_ind_direct_IO(int rw, struct kiocb *iocb,
const struct iovec *iov, loff_t offset,
unsigned long nr_segs);
extern int ext4_ind_calc_metadata_amount(struct inode *inode, sector_t lblock);
-extern int ext4_ind_trans_blocks(struct inode *inode, int nrblocks, int chunk);
+extern int ext4_ind_trans_blocks(struct inode *inode, int nrblocks);
extern void ext4_ind_truncate(handle_t *, struct inode *inode);
extern int ext4_free_hole_blocks(handle_t *handle, struct inode *inode,
ext4_lblk_t first, ext4_lblk_t stop);
diff --git a/fs/ext4/indirect.c b/fs/ext4/indirect.c
index b8d5d35..f7742f0 100644
--- a/fs/ext4/indirect.c
+++ b/fs/ext4/indirect.c
@@ -779,27 +779,18 @@ int ext4_ind_calc_metadata_amount(struct inode *inode, sector_t lblock)
return (blk_bits / EXT4_ADDR_PER_BLOCK_BITS(inode->i_sb)) + 1;
}
-int ext4_ind_trans_blocks(struct inode *inode, int nrblocks, int chunk)
+/*
+ * Calculate number of indirect blocks touched by mapping @nrblocks logically
+ * contiguous blocks
+ */
+int ext4_ind_trans_blocks(struct inode *inode, int nrblocks)
{
- int indirects;
-
- /* if nrblocks are contiguous */
- if (chunk) {
- /*
- * With N contiguous data blocks, we need at most
- * N/EXT4_ADDR_PER_BLOCK(inode->i_sb) + 1 indirect blocks,
- * 2 dindirect blocks, and 1 tindirect block
- */
- return DIV_ROUND_UP(nrblocks,
- EXT4_ADDR_PER_BLOCK(inode->i_sb)) + 4;
- }
/*
- * if nrblocks are not contiguous, worse case, each block touch
- * a indirect block, and each indirect block touch a double indirect
- * block, plus a triple indirect block
+ * With N contiguous data blocks, we need at most
+ * N/EXT4_ADDR_PER_BLOCK(inode->i_sb) + 1 indirect blocks,
+ * 2 dindirect blocks, and 1 tindirect block
*/
- indirects = nrblocks * 2 + 1;
- return indirects;
+ return DIV_ROUND_UP(nrblocks, EXT4_ADDR_PER_BLOCK(inode->i_sb)) + 4;
}
/*
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index 80c710a..23d9a44 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -4653,7 +4653,7 @@ int ext4_getattr(struct vfsmount *mnt, struct dentry *dentry,
static int ext4_index_trans_blocks(struct inode *inode, int nrblocks, int chunk)
{
if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)))
- return ext4_ind_trans_blocks(inode, nrblocks, chunk);
+ return ext4_ind_trans_blocks(inode, nrblocks);
return ext4_ext_index_trans_blocks(inode, nrblocks, chunk);
}
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