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ext4: Convert callers of ext4_get_blocks() to use ext4_map_blocks()

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This saves a huge amount of stack space by avoiding unnecesary struct
buffer_head's from being allocated on the stack.

In addition, to make the code easier to understand, collapse and
refactor ext4_get_block(), ext4_get_block_write(),
noalloc_get_block_write(), into a single function.

Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
This commit is contained in:
Theodore Ts'o
2010-05-16 20:00:00 -04:00
parent e35fd6609b
commit 2ed886852a
3 changed files with 152 additions and 231 deletions
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12
fs/ext4/dir.c
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@@ -128,14 +128,14 @@ static int ext4_readdir(struct file *filp,
offset = filp->f_pos & (sb->s_blocksize - 1);
while (!error && !stored && filp->f_pos < inode->i_size) {
ext4_lblk_t blk = filp->f_pos >> EXT4_BLOCK_SIZE_BITS(sb);
struct buffer_head map_bh;
struct ext4_map_blocks map;
struct buffer_head *bh = NULL;
map_bh.b_state = 0;
err = ext4_get_blocks(NULL, inode, blk, 1, &map_bh, 0);
map.m_lblk = filp->f_pos >> EXT4_BLOCK_SIZE_BITS(sb);
map.m_len = 1;
err = ext4_map_blocks(NULL, inode, &map, 0);
if (err > 0) {
pgoff_t index = map_bh.b_blocknr >>
pgoff_t index = map.m_pblk >>
(PAGE_CACHE_SHIFT - inode->i_blkbits);
if (!ra_has_index(&filp->f_ra, index))
page_cache_sync_readahead(
@@ -143,7 +143,7 @@ static int ext4_readdir(struct file *filp,
&filp->f_ra, filp,
index, 1);
filp->f_ra.prev_pos = (loff_t)index << PAGE_CACHE_SHIFT;
bh = ext4_bread(NULL, inode, blk, 0, &err);
bh = ext4_bread(NULL, inode, map.m_lblk, 0, &err);
}
/*