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Btrfs: __btrfs_buffered_write: Reserve/release extents aligned to block size

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Currently, the code reserves/releases extents in multiples of PAGE_CACHE_SIZE
units. Fix this by doing reservation/releases in block size units.

Signed-off-by: Chandan Rajendra <chandan@linux.vnet.ibm.com>
Signed-off-by: David Sterba <dsterba@suse.com>
This commit is contained in:
Chandan Rajendra 2016-01-21 15:55:53 +05:30 committed by David Sterba
parent e410e34fad
commit 2e78c927d7
2 changed files with 33 additions and 13 deletions
repo.diff.show_diff_stats Download patch file Download diff file Expand all files Collapse all files

3
fs/btrfs/ctree.h
View file

@ -2353,6 +2353,9 @@ struct btrfs_map_token {
unsigned long offset;
};
#define BTRFS_BYTES_TO_BLKS(fs_info, bytes) \
((bytes) >> (fs_info)->sb->s_blocksize_bits)
static inline void btrfs_init_map_token (struct btrfs_map_token *token)
{
token->kaddr = NULL;

43
fs/btrfs/file.c
View file

@ -498,7 +498,7 @@ int btrfs_dirty_pages(struct btrfs_root *root, struct inode *inode,
loff_t isize = i_size_read(inode);
start_pos = pos & ~((u64)root->sectorsize - 1);
num_bytes = ALIGN(write_bytes + pos - start_pos, root->sectorsize);
num_bytes = round_up(write_bytes + pos - start_pos, root->sectorsize);
end_of_last_block = start_pos + num_bytes - 1;
err = btrfs_set_extent_delalloc(inode, start_pos, end_of_last_block,
@ -1379,16 +1379,19 @@ static noinline int prepare_pages(struct inode *inode, struct page **pages,
static noinline int
lock_and_cleanup_extent_if_need(struct inode *inode, struct page **pages,
size_t num_pages, loff_t pos,
size_t write_bytes,
u64 *lockstart, u64 *lockend,
struct extent_state **cached_state)
{
struct btrfs_root *root = BTRFS_I(inode)->root;
u64 start_pos;
u64 last_pos;
int i;
int ret = 0;
start_pos = pos & ~((u64)PAGE_CACHE_SIZE - 1);
last_pos = start_pos + ((u64)num_pages << PAGE_CACHE_SHIFT) - 1;
start_pos = round_down(pos, root->sectorsize);
last_pos = start_pos
+ round_up(pos + write_bytes - start_pos, root->sectorsize) - 1;
if (start_pos < inode->i_size) {
struct btrfs_ordered_extent *ordered;
@ -1503,6 +1506,7 @@ static noinline ssize_t __btrfs_buffered_write(struct file *file,
while (iov_iter_count(i) > 0) {
size_t offset = pos & (PAGE_CACHE_SIZE - 1);
size_t sector_offset;
size_t write_bytes = min(iov_iter_count(i),
nrptrs * (size_t)PAGE_CACHE_SIZE -
offset);
@ -1511,6 +1515,8 @@ static noinline ssize_t __btrfs_buffered_write(struct file *file,
size_t reserve_bytes;
size_t dirty_pages;
size_t copied;
size_t dirty_sectors;
size_t num_sectors;
WARN_ON(num_pages > nrptrs);
@ -1523,7 +1529,9 @@ static noinline ssize_t __btrfs_buffered_write(struct file *file,
break;
}
reserve_bytes = num_pages << PAGE_CACHE_SHIFT;
sector_offset = pos & (root->sectorsize - 1);
reserve_bytes = round_up(write_bytes + sector_offset,
root->sectorsize);
if (BTRFS_I(inode)->flags & (BTRFS_INODE_NODATACOW |
BTRFS_INODE_PREALLOC)) {
@ -1542,7 +1550,9 @@ static noinline ssize_t __btrfs_buffered_write(struct file *file,
*/
num_pages = DIV_ROUND_UP(write_bytes + offset,
PAGE_CACHE_SIZE);
reserve_bytes = num_pages << PAGE_CACHE_SHIFT;
reserve_bytes = round_up(write_bytes
+ sector_offset,
root->sectorsize);
goto reserve_metadata;
}
}
@ -1576,8 +1586,8 @@ static noinline ssize_t __btrfs_buffered_write(struct file *file,
break;
ret = lock_and_cleanup_extent_if_need(inode, pages, num_pages,
pos, &lockstart, &lockend,
&cached_state);
pos, write_bytes, &lockstart,
&lockend, &cached_state);
if (ret < 0) {
if (ret == -EAGAIN)
goto again;
@ -1612,9 +1622,16 @@ static noinline ssize_t __btrfs_buffered_write(struct file *file,
* we still have an outstanding extent for the chunk we actually
* managed to copy.
*/
if (num_pages > dirty_pages) {
release_bytes = (num_pages - dirty_pages) <<
PAGE_CACHE_SHIFT;
num_sectors = BTRFS_BYTES_TO_BLKS(root->fs_info,
reserve_bytes);
dirty_sectors = round_up(copied + sector_offset,
root->sectorsize);
dirty_sectors = BTRFS_BYTES_TO_BLKS(root->fs_info,
dirty_sectors);
if (num_sectors > dirty_sectors) {
release_bytes = (write_bytes - copied)
& ~((u64)root->sectorsize - 1);
if (copied > 0) {
spin_lock(&BTRFS_I(inode)->lock);
BTRFS_I(inode)->outstanding_extents++;
@ -1633,7 +1650,8 @@ static noinline ssize_t __btrfs_buffered_write(struct file *file,
}
}
release_bytes = dirty_pages << PAGE_CACHE_SHIFT;
release_bytes = round_up(copied + sector_offset,
root->sectorsize);
if (copied > 0)
ret = btrfs_dirty_pages(root, inode, pages,
@ -1654,8 +1672,7 @@ static noinline ssize_t __btrfs_buffered_write(struct file *file,
if (only_release_metadata && copied > 0) {
lockstart = round_down(pos, root->sectorsize);
lockend = lockstart +
(dirty_pages << PAGE_CACHE_SHIFT) - 1;
lockend = round_up(pos + copied, root->sectorsize) - 1;
set_extent_bit(&BTRFS_I(inode)->io_tree, lockstart,
lockend, EXTENT_NORESERVE, NULL,