summaryrefslogtreecommitdiff
path: root/fs/ext4/mballoc.c
diff options
context:
space:
mode:
authorAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>2008-10-09 10:56:23 -0400
committerTheodore Ts'o <tytso@mit.edu>2008-10-09 10:56:23 -0400
commita30d542a0035b886ffaafd0057ced0a2b28c3a4f (patch)
tree9e677eaf4eb1611701828554b27a1b0b0ae523fd /fs/ext4/mballoc.c
parentc4a0c46ec92c194c873232b88debce4e1a448483 (diff)
downloadlwn-a30d542a0035b886ffaafd0057ced0a2b28c3a4f.tar.gz
lwn-a30d542a0035b886ffaafd0057ced0a2b28c3a4f.zip
ext4: Make sure all the block allocation paths reserve blocks
With delayed allocation we need to make sure block are reserved before we attempt to allocate them. Otherwise we get block allocation failure (ENOSPC) during writepages which cannot be handled. This would mean silent data loss (We do a printk stating data will be lost). This patch updates the DIO and fallocate code path to do block reservation before block allocation. This is needed to make sure parallel DIO and fallocate request doesn't take block out of delayed reserve space. When free blocks count go below a threshold we switch to a slow patch which looks at other CPU's accumulated percpu counter values. Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Diffstat (limited to 'fs/ext4/mballoc.c')
-rw-r--r--fs/ext4/mballoc.c23
1 files changed, 13 insertions, 10 deletions
diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c
index 0db2ccfa0dad..2c10b5058a8d 100644
--- a/fs/ext4/mballoc.c
+++ b/fs/ext4/mballoc.c
@@ -2975,9 +2975,15 @@ ext4_mb_mark_diskspace_used(struct ext4_allocation_context *ac,
* at write_begin() time for delayed allocation
* do not double accounting
*/
- if (!(ac->ac_flags & EXT4_MB_DELALLOC_RESERVED))
- percpu_counter_sub(&sbi->s_freeblocks_counter,
- ac->ac_b_ex.fe_len);
+ if (!(ac->ac_flags & EXT4_MB_DELALLOC_RESERVED) &&
+ ac->ac_o_ex.fe_len != ac->ac_b_ex.fe_len) {
+ /*
+ * we allocated less blocks than we calimed
+ * Add the difference back
+ */
+ percpu_counter_add(&sbi->s_freeblocks_counter,
+ ac->ac_o_ex.fe_len - ac->ac_b_ex.fe_len);
+ }
if (sbi->s_log_groups_per_flex) {
ext4_group_t flex_group = ext4_flex_group(sbi,
@@ -4389,14 +4395,11 @@ ext4_fsblk_t ext4_mb_new_blocks(handle_t *handle,
/*
* With delalloc we already reserved the blocks
*/
- ar->len = ext4_has_free_blocks(sbi, ar->len);
- }
-
- if (ar->len == 0) {
- *errp = -ENOSPC;
- return 0;
+ if (ext4_claim_free_blocks(sbi, ar->len)) {
+ *errp = -ENOSPC;
+ return 0;
+ }
}
-
while (ar->len && DQUOT_ALLOC_BLOCK(ar->inode, ar->len)) {
ar->flags |= EXT4_MB_HINT_NOPREALLOC;
ar->len--;