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ext4: remove metadata reservation checks
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Commit 27dd438 ("ext4: introduce reserved space") reserves 2% of
the file system space to make sure metadata allocations will always
succeed.  Given that, tracking the reservation of metadata blocks is
no longer necessary.

Signed-off-by: Theodore Ts'o <tytso@mit.edu>
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Theodore Ts'o committed Jul 15, 2014
1 parent d5e03cb commit 71d4f7d
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Showing 5 changed files with 7 additions and 141 deletions.
1 change: 0 additions & 1 deletion fs/ext4/balloc.c
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Original file line number Diff line number Diff line change
Expand Up @@ -639,7 +639,6 @@ ext4_fsblk_t ext4_new_meta_blocks(handle_t *handle, struct inode *inode,
if (!(*errp) &&
ext4_test_inode_state(inode, EXT4_STATE_DELALLOC_RESERVED)) {
spin_lock(&EXT4_I(inode)->i_block_reservation_lock);
EXT4_I(inode)->i_allocated_meta_blocks += ar.len;
spin_unlock(&EXT4_I(inode)->i_block_reservation_lock);
dquot_alloc_block_nofail(inode,
EXT4_C2B(EXT4_SB(inode->i_sb), ar.len));
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1 change: 0 additions & 1 deletion fs/ext4/ext4.h
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Original file line number Diff line number Diff line change
Expand Up @@ -591,7 +591,6 @@ enum {
#define EXT4_FREE_BLOCKS_NO_QUOT_UPDATE 0x0008
#define EXT4_FREE_BLOCKS_NOFREE_FIRST_CLUSTER 0x0010
#define EXT4_FREE_BLOCKS_NOFREE_LAST_CLUSTER 0x0020
#define EXT4_FREE_BLOCKS_RESERVE 0x0040

/*
* ioctl commands
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3 changes: 1 addition & 2 deletions fs/ext4/extents.c
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Original file line number Diff line number Diff line change
Expand Up @@ -1808,8 +1808,7 @@ static void ext4_ext_try_to_merge_up(handle_t *handle,

brelse(path[1].p_bh);
ext4_free_blocks(handle, inode, NULL, blk, 1,
EXT4_FREE_BLOCKS_METADATA | EXT4_FREE_BLOCKS_FORGET |
EXT4_FREE_BLOCKS_RESERVE);
EXT4_FREE_BLOCKS_METADATA | EXT4_FREE_BLOCKS_FORGET);
}

/*
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128 changes: 5 additions & 123 deletions fs/ext4/inode.c
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Original file line number Diff line number Diff line change
Expand Up @@ -324,18 +324,6 @@ qsize_t *ext4_get_reserved_space(struct inode *inode)
}
#endif

/*
* Calculate the number of metadata blocks need to reserve
* to allocate a block located at @lblock
*/
static int ext4_calc_metadata_amount(struct inode *inode, ext4_lblk_t lblock)
{
if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
return ext4_ext_calc_metadata_amount(inode, lblock);

return ext4_ind_calc_metadata_amount(inode, lblock);
}

/*
* Called with i_data_sem down, which is important since we can call
* ext4_discard_preallocations() from here.
Expand All @@ -357,35 +345,10 @@ void ext4_da_update_reserve_space(struct inode *inode,
used = ei->i_reserved_data_blocks;
}

if (unlikely(ei->i_allocated_meta_blocks > ei->i_reserved_meta_blocks)) {
ext4_warning(inode->i_sb, "ino %lu, allocated %d "
"with only %d reserved metadata blocks "
"(releasing %d blocks with reserved %d data blocks)",
inode->i_ino, ei->i_allocated_meta_blocks,
ei->i_reserved_meta_blocks, used,
ei->i_reserved_data_blocks);
WARN_ON(1);
ei->i_allocated_meta_blocks = ei->i_reserved_meta_blocks;
}

/* Update per-inode reservations */
ei->i_reserved_data_blocks -= used;
ei->i_reserved_meta_blocks -= ei->i_allocated_meta_blocks;
percpu_counter_sub(&sbi->s_dirtyclusters_counter,
used + ei->i_allocated_meta_blocks);
ei->i_allocated_meta_blocks = 0;
percpu_counter_sub(&sbi->s_dirtyclusters_counter, used);

if (ei->i_reserved_data_blocks == 0) {
/*
* We can release all of the reserved metadata blocks
* only when we have written all of the delayed
* allocation blocks.
*/
percpu_counter_sub(&sbi->s_dirtyclusters_counter,
ei->i_reserved_meta_blocks);
ei->i_reserved_meta_blocks = 0;
ei->i_da_metadata_calc_len = 0;
}
spin_unlock(&EXT4_I(inode)->i_block_reservation_lock);

/* Update quota subsystem for data blocks */
Expand Down Expand Up @@ -1221,49 +1184,6 @@ static int ext4_journalled_write_end(struct file *file,
return ret ? ret : copied;
}

/*
* Reserve a metadata for a single block located at lblock
*/
static int ext4_da_reserve_metadata(struct inode *inode, ext4_lblk_t lblock)
{
struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
struct ext4_inode_info *ei = EXT4_I(inode);
unsigned int md_needed;
ext4_lblk_t save_last_lblock;
int save_len;

/*
* recalculate the amount of metadata blocks to reserve
* in order to allocate nrblocks
* worse case is one extent per block
*/
spin_lock(&ei->i_block_reservation_lock);
/*
* ext4_calc_metadata_amount() has side effects, which we have
* to be prepared undo if we fail to claim space.
*/
save_len = ei->i_da_metadata_calc_len;
save_last_lblock = ei->i_da_metadata_calc_last_lblock;
md_needed = EXT4_NUM_B2C(sbi,
ext4_calc_metadata_amount(inode, lblock));
trace_ext4_da_reserve_space(inode, md_needed);

/*
* We do still charge estimated metadata to the sb though;
* we cannot afford to run out of free blocks.
*/
if (ext4_claim_free_clusters(sbi, md_needed, 0)) {
ei->i_da_metadata_calc_len = save_len;
ei->i_da_metadata_calc_last_lblock = save_last_lblock;
spin_unlock(&ei->i_block_reservation_lock);
return -ENOSPC;
}
ei->i_reserved_meta_blocks += md_needed;
spin_unlock(&ei->i_block_reservation_lock);

return 0; /* success */
}

/*
* Reserve a single cluster located at lblock
*/
Expand All @@ -1273,8 +1193,6 @@ static int ext4_da_reserve_space(struct inode *inode, ext4_lblk_t lblock)
struct ext4_inode_info *ei = EXT4_I(inode);
unsigned int md_needed;
int ret;
ext4_lblk_t save_last_lblock;
int save_len;

/*
* We will charge metadata quota at writeout time; this saves
Expand All @@ -1295,25 +1213,15 @@ static int ext4_da_reserve_space(struct inode *inode, ext4_lblk_t lblock)
* ext4_calc_metadata_amount() has side effects, which we have
* to be prepared undo if we fail to claim space.
*/
save_len = ei->i_da_metadata_calc_len;
save_last_lblock = ei->i_da_metadata_calc_last_lblock;
md_needed = EXT4_NUM_B2C(sbi,
ext4_calc_metadata_amount(inode, lblock));
trace_ext4_da_reserve_space(inode, md_needed);
md_needed = 0;
trace_ext4_da_reserve_space(inode, 0);

/*
* We do still charge estimated metadata to the sb though;
* we cannot afford to run out of free blocks.
*/
if (ext4_claim_free_clusters(sbi, md_needed + 1, 0)) {
ei->i_da_metadata_calc_len = save_len;
ei->i_da_metadata_calc_last_lblock = save_last_lblock;
if (ext4_claim_free_clusters(sbi, 1, 0)) {
spin_unlock(&ei->i_block_reservation_lock);
dquot_release_reservation_block(inode, EXT4_C2B(sbi, 1));
return -ENOSPC;
}
ei->i_reserved_data_blocks++;
ei->i_reserved_meta_blocks += md_needed;
spin_unlock(&ei->i_block_reservation_lock);

return 0; /* success */
Expand Down Expand Up @@ -1346,20 +1254,6 @@ static void ext4_da_release_space(struct inode *inode, int to_free)
}
ei->i_reserved_data_blocks -= to_free;

if (ei->i_reserved_data_blocks == 0) {
/*
* We can release all of the reserved metadata blocks
* only when we have written all of the delayed
* allocation blocks.
* Note that in case of bigalloc, i_reserved_meta_blocks,
* i_reserved_data_blocks, etc. refer to number of clusters.
*/
percpu_counter_sub(&sbi->s_dirtyclusters_counter,
ei->i_reserved_meta_blocks);
ei->i_reserved_meta_blocks = 0;
ei->i_da_metadata_calc_len = 0;
}

/* update fs dirty data blocks counter */
percpu_counter_sub(&sbi->s_dirtyclusters_counter, to_free);

Expand Down Expand Up @@ -1500,10 +1394,6 @@ static void ext4_print_free_blocks(struct inode *inode)
ext4_msg(sb, KERN_CRIT, "Block reservation details");
ext4_msg(sb, KERN_CRIT, "i_reserved_data_blocks=%u",
ei->i_reserved_data_blocks);
ext4_msg(sb, KERN_CRIT, "i_reserved_meta_blocks=%u",
ei->i_reserved_meta_blocks);
ext4_msg(sb, KERN_CRIT, "i_allocated_meta_blocks=%u",
ei->i_allocated_meta_blocks);
return;
}

Expand Down Expand Up @@ -1620,13 +1510,6 @@ static int ext4_da_map_blocks(struct inode *inode, sector_t iblock,
retval = ret;
goto out_unlock;
}
} else {
ret = ext4_da_reserve_metadata(inode, iblock);
if (ret) {
/* not enough space to reserve */
retval = ret;
goto out_unlock;
}
}

ret = ext4_es_insert_extent(inode, map->m_lblk, map->m_len,
Expand Down Expand Up @@ -2843,8 +2726,7 @@ int ext4_alloc_da_blocks(struct inode *inode)
{
trace_ext4_alloc_da_blocks(inode);

if (!EXT4_I(inode)->i_reserved_data_blocks &&
!EXT4_I(inode)->i_reserved_meta_blocks)
if (!EXT4_I(inode)->i_reserved_data_blocks)
return 0;

/*
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15 changes: 1 addition & 14 deletions fs/ext4/mballoc.c
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Original file line number Diff line number Diff line change
Expand Up @@ -4627,7 +4627,6 @@ void ext4_free_blocks(handle_t *handle, struct inode *inode,
struct buffer_head *gd_bh;
ext4_group_t block_group;
struct ext4_sb_info *sbi;
struct ext4_inode_info *ei = EXT4_I(inode);
struct ext4_buddy e4b;
unsigned int count_clusters;
int err = 0;
Expand Down Expand Up @@ -4838,19 +4837,7 @@ void ext4_free_blocks(handle_t *handle, struct inode *inode,
&sbi->s_flex_groups[flex_group].free_clusters);
}

if (flags & EXT4_FREE_BLOCKS_RESERVE && ei->i_reserved_data_blocks) {
percpu_counter_add(&sbi->s_dirtyclusters_counter,
count_clusters);
spin_lock(&ei->i_block_reservation_lock);
if (flags & EXT4_FREE_BLOCKS_METADATA)
ei->i_reserved_meta_blocks += count_clusters;
else
ei->i_reserved_data_blocks += count_clusters;
spin_unlock(&ei->i_block_reservation_lock);
if (!(flags & EXT4_FREE_BLOCKS_NO_QUOT_UPDATE))
dquot_reclaim_block(inode,
EXT4_C2B(sbi, count_clusters));
} else if (!(flags & EXT4_FREE_BLOCKS_NO_QUOT_UPDATE))
if (!(flags & EXT4_FREE_BLOCKS_NO_QUOT_UPDATE))
dquot_free_block(inode, EXT4_C2B(sbi, count_clusters));
percpu_counter_add(&sbi->s_freeclusters_counter, count_clusters);

Expand Down

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