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ext4: Clean up ext4_get_blocks() so it does not depend on bh_result->b_state 

The ext4_get_blocks() function was depending on the value of
bh_result->b_state as an input parameter to decide whether or not
update the delalloc accounting statistics by calling
ext4_da_update_reserve_space().  We now use a separate flag,
EXT4_GET_BLOCKS_UPDATE_RESERVE_SPACE, to requests this update, so that
all callers of ext4_get_blocks() can clear map_bh.b_state before
calling ext4_get_blocks() without worrying about any consistency
issues.

Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
This commit is contained in:
Theodore Ts'o 2009-05-14 13:57:08 -04:00
parent 2fa3cdfb31
commit 2ac3b6e00a
2 changed files with 41 additions and 30 deletions
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15
fs/ext4/ext4.h
View File

@ -318,16 +318,21 @@ struct ext4_new_group_data {
*/
/* Allocate any needed blocks and/or convert an unitialized
extent to be an initialized ext4 */
#define EXT4_GET_BLOCKS_CREATE 1
#define EXT4_GET_BLOCKS_CREATE 0x0001
/* Request the creation of an unitialized extent */
#define EXT4_GET_BLOCKS_UNINIT_EXT 2
#define EXT4_GET_BLOCKS_UNINIT_EXT 0x0002
#define EXT4_GET_BLOCKS_CREATE_UNINIT_EXT (EXT4_GET_BLOCKS_UNINIT_EXT|\
EXT4_GET_BLOCKS_CREATE)
/* Update the ext4_inode_info i_disksize field */
#define EXT4_GET_BLOCKS_EXTEND_DISKSIZE 4
#define EXT4_GET_BLOCKS_EXTEND_DISKSIZE 0x0004
/* Caller is from the delayed allocation writeout path,
so the filesystem blocks have already been accounted for */
#define EXT4_GET_BLOCKS_DELALLOC_RESERVE 8
so set the magic i_delalloc_reserve_flag after taking the
inode allocation semaphore for */
#define EXT4_GET_BLOCKS_DELALLOC_RESERVE 0x0008
/* Call ext4_da_update_reserve_space() after successfully
allocating the blocks */
#define EXT4_GET_BLOCKS_UPDATE_RESERVE_SPACE 0x0010
/*
* ioctl commands

56
fs/ext4/inode.c
View File

@ -1234,16 +1234,15 @@ int ext4_get_blocks(handle_t *handle, struct inode *inode, sector_t block,
}
}
if (flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE) {
if (flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE)
EXT4_I(inode)->i_delalloc_reserved_flag = 0;
/*
* Update reserved blocks/metadata blocks
* after successful block allocation
* which were deferred till now
*/
if ((retval > 0) && buffer_delay(bh))
ext4_da_update_reserve_space(inode, retval);
}
/*
* Update reserved blocks/metadata blocks after successful
* block allocation which had been deferred till now.
*/
if ((retval > 0) && (flags & EXT4_GET_BLOCKS_UPDATE_RESERVE_SPACE))
ext4_da_update_reserve_space(inode, retval);
up_write((&EXT4_I(inode)->i_data_sem));
return retval;
@ -2015,7 +2014,7 @@ static void ext4_print_free_blocks(struct inode *inode)
*/
static int mpage_da_map_blocks(struct mpage_da_data *mpd)
{
int err, blks;
int err, blks, get_blocks_flags;
struct buffer_head new;
sector_t next = mpd->b_blocknr;
unsigned max_blocks = mpd->b_size >> mpd->inode->i_blkbits;
@ -2040,23 +2039,30 @@ static int mpage_da_map_blocks(struct mpage_da_data *mpd)
BUG_ON(!handle);
/*
* We need to make sure the BH_Delay flag is passed down to
* ext4_da_get_block_write(), since it calls ext4_get_blocks()
* with the EXT4_GET_BLOCKS_DELALLOC_RESERVE flag. This flag
* causes ext4_get_blocks() to call
* ext4_da_update_reserve_space() if the passed buffer head
* has the BH_Delay flag set. In the future, once we clean up
* the interfaces to ext4_get_blocks(), we should pass in a
* separate flag which requests that the delayed allocation
* statistics should be updated, instead of depending on the
* state information getting passed down via the map_bh's
* state bitmasks plus the magic
* EXT4_GET_BLOCKS_DELALLOC_RESERVE flag.
* Call ext4_get_blocks() to allocate any delayed allocation
* blocks, or to convert an uninitialized extent to be
* initialized (in the case where we have written into
* one or more preallocated blocks).
*
* We pass in the magic EXT4_GET_BLOCKS_DELALLOC_RESERVE to
* indicate that we are on the delayed allocation path. This
* affects functions in many different parts of the allocation
* call path. This flag exists primarily because we don't
* want to change *many* call functions, so ext4_get_blocks()
* will set the magic i_delalloc_reserved_flag once the
* inode's allocation semaphore is taken.
*
* If the blocks in questions were delalloc blocks, set
* EXT4_GET_BLOCKS_DELALLOC_RESERVE so the delalloc accounting
* variables are updated after the blocks have been allocated.
*/
new.b_state = mpd->b_state & (1 << BH_Delay);
new.b_state = 0;
get_blocks_flags = (EXT4_GET_BLOCKS_CREATE |
EXT4_GET_BLOCKS_DELALLOC_RESERVE);
if (mpd->b_state & (1 << BH_Delay))
get_blocks_flags |= EXT4_GET_BLOCKS_UPDATE_RESERVE_SPACE;
blks = ext4_get_blocks(handle, mpd->inode, next, max_blocks,
&new, EXT4_GET_BLOCKS_CREATE|
EXT4_GET_BLOCKS_DELALLOC_RESERVE);
&new, get_blocks_flags);
if (blks < 0) {
err = blks;
/*