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Date: Tue, 3 Jun 2008 22:59:37 +0530
From: "Aneesh Kumar K.V" <aneesh.kumar@...ux.vnet.ibm.com>
To: cmm@...ibm.com
Cc: linux-ext4@...r.kernel.org,
"Aneesh Kumar K.V" <aneesh.kumar@...ux.vnet.ibm.com>
Subject: [PATCH] ext4: delalloc block reservation fix
a) We need to decrement the meta data blocks that got allocated
from percpu s_freeblocks_counter
b) We need to protect the reservation block counter so that
reserve and release space doesn't race each other.
c) don't check for free space in ext4_mb_new_blocks with delalloc
We already reserved the space.
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@...ux.vnet.ibm.com>
---
fs/ext4/balloc.c | 9 +++++++++
fs/ext4/ext4_i.h | 2 ++
fs/ext4/inode.c | 36 +++++++++++++++++++++++-------------
fs/ext4/mballoc.c | 7 ++++++-
fs/ext4/super.c | 2 ++
5 files changed, 42 insertions(+), 14 deletions(-)
diff --git a/fs/ext4/balloc.c b/fs/ext4/balloc.c
index 71b184c..bd18ceb 100644
--- a/fs/ext4/balloc.c
+++ b/fs/ext4/balloc.c
@@ -1959,6 +1959,15 @@ ext4_fsblk_t ext4_new_meta_block(handle_t *handle, struct inode *inode,
ar.goal = goal;
ar.len = 1;
ret = ext4_mb_new_blocks(handle, &ar, errp);
+ /*
+ * Account for the allocated meta blocks
+ */
+ if (!(*errp)) {
+ 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);
+ }
+
return ret;
}
ext4_fsblk_t ext4_new_meta_blocks(handle_t *handle, struct inode *inode,
diff --git a/fs/ext4/ext4_i.h b/fs/ext4/ext4_i.h
index 425518e..3d08e5b 100644
--- a/fs/ext4/ext4_i.h
+++ b/fs/ext4/ext4_i.h
@@ -166,7 +166,9 @@ struct ext4_inode_info {
/* allocation reservation info for delalloc */
unsigned long i_reserved_data_blocks;
unsigned long i_reserved_meta_blocks;
+ unsigned long i_allocated_meta_blocks;
unsigned short i_delalloc_reserved_flag;
+ spinlock_t i_block_reservation_lock;
};
#endif /* _EXT4_I */
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index 1695ecc..2e485a3 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -1426,11 +1426,12 @@ static int ext4_da_reserve_space(struct inode *inode, int nrblocks)
struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
unsigned long md_needed, mdblocks, total = 0;
- /*
- * calculate the amount of metadata blocks to reserve
- * in order to allocate nrblocks
- * worse case is one extent per block
- */
+ /*
+ * recalculate the amount of metadata blocks to reserve
+ * in order to allocate nrblocks
+ * worse case is one extent per block
+ */
+ spin_lock(&EXT4_I(inode)->i_block_reservation_lock);
total = EXT4_I(inode)->i_reserved_data_blocks + nrblocks;
mdblocks = ext4_ext_calc_metadata_amount(inode, total);
BUG_ON(mdblocks < EXT4_I(inode)->i_reserved_meta_blocks);
@@ -1438,42 +1439,51 @@ static int ext4_da_reserve_space(struct inode *inode, int nrblocks)
md_needed = mdblocks - EXT4_I(inode)->i_reserved_meta_blocks;
total = md_needed + nrblocks;
- if (ext4_has_free_blocks(sbi, total) < total)
+ if (ext4_has_free_blocks(sbi, total) < total) {
+ spin_unlock(&EXT4_I(inode)->i_block_reservation_lock);
return -ENOSPC;
+ }
/* reduce fs free blocks counter */
percpu_counter_sub(&sbi->s_freeblocks_counter, total);
EXT4_I(inode)->i_reserved_data_blocks += nrblocks;
- EXT4_I(inode)->i_reserved_meta_blocks += md_needed;
+ EXT4_I(inode)->i_reserved_meta_blocks = mdblocks;
+ spin_unlock(&EXT4_I(inode)->i_block_reservation_lock);
return 0; /* success */
}
void ext4_da_release_space(struct inode *inode, int used, int to_free)
{
struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
- int total, mdb, release;
+ int total, mdb, mdb_free, release;
- /* calculate the number of metablocks still need to be reserved */
+ spin_lock(&EXT4_I(inode)->i_block_reservation_lock);
+ /* recalculate the number of metablocks still need to be reserved */
total = EXT4_I(inode)->i_reserved_data_blocks - used - to_free;
mdb = ext4_ext_calc_metadata_amount(inode, total);
/* figure out how many metablocks to release */
BUG_ON(mdb > EXT4_I(inode)->i_reserved_meta_blocks);
- mdb = EXT4_I(inode)->i_reserved_meta_blocks - mdb;
+ mdb_free = EXT4_I(inode)->i_reserved_meta_blocks - mdb;
+
+ /* Account for allocated meta_blocks */
+ mdb_free -= EXT4_I(inode)->i_allocated_meta_blocks;
- release = to_free + mdb;
+ release = to_free + mdb_free;
/* update fs free blocks counter for truncate case */
percpu_counter_add(&sbi->s_freeblocks_counter, release);
/* update per-inode reservations */
BUG_ON(used + to_free > EXT4_I(inode)->i_reserved_data_blocks);
- EXT4_I(inode)->i_reserved_data_blocks -= used + to_free;
+ EXT4_I(inode)->i_reserved_data_blocks -= (used + to_free);
BUG_ON(mdb > EXT4_I(inode)->i_reserved_meta_blocks);
- EXT4_I(inode)->i_reserved_meta_blocks -= mdb;
+ EXT4_I(inode)->i_reserved_meta_blocks = mdb;
+ EXT4_I(inode)->i_allocated_meta_blocks = 0;
+ spin_unlock(&EXT4_I(inode)->i_block_reservation_lock);
}
static void ext4_da_page_release_reservation(struct page *page,
diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c
index a7bdacb..09922ae 100644
--- a/fs/ext4/mballoc.c
+++ b/fs/ext4/mballoc.c
@@ -4052,7 +4052,12 @@ ext4_fsblk_t ext4_mb_new_blocks(handle_t *handle,
&(ar->len), errp);
return block;
}
- ar->len = ext4_has_free_blocks(sbi, ar->len);
+ if (!EXT4_I(ar->inode)->i_delalloc_reserved_flag) {
+ /*
+ * With delalloc we already reserved the blocks
+ */
+ ar->len = ext4_has_free_blocks(sbi, ar->len);
+ }
if (ar->len == 0) {
*errp = -ENOSPC;
diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index 073bb2c..ee036af 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -574,7 +574,9 @@ static struct inode *ext4_alloc_inode(struct super_block *sb)
spin_lock_init(&ei->i_prealloc_lock);
ei->i_reserved_data_blocks = 0;
ei->i_reserved_meta_blocks = 0;
+ ei->i_allocated_meta_blocks = 0;
ei->i_delalloc_reserved_flag = 0;
+ spin_lock_init(&(ei->i_block_reservation_lock));
return &ei->vfs_inode;
}
--
1.5.5.1.357.g1af8b.dirty
--
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