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Btrfs: fix a bug in checking whether a inode is already in log

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This is based on Josef's "Btrfs: turbo charge fsync".

The current btrfs checks if an inode is in log by comparing
root's last_log_commit to inode's last_sub_trans[2].

But the problem is that this root->last_log_commit is shared among
inodes.

Say we have N inodes to be logged, after the first inode,
root's last_log_commit is updated and the N-1 remained files will
be skipped.

This fixes the bug by keeping a local copy of root's last_log_commit
inside each inode and this local copy will be maintained itself.

[1]: we regard each log transaction as a subset of btrfs's transaction,
i.e. sub_trans

Signed-off-by: Liu Bo <bo.li.liu@oracle.com>
This commit is contained in:
Liu Bo 2012-08-29 01:07:55 -06:00 committed by Chris Mason
parent 321f0e7022
commit 46d8bc3424
4 changed files with 10 additions and 8 deletions
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14
fs/btrfs/btrfs_inode.h
View file

@ -144,6 +144,9 @@ struct btrfs_inode {
/* flags field from the on disk inode */
u32 flags;
/* a local copy of root's last_log_commit */
unsigned long last_log_commit;
/*
* Counters to keep track of the number of extent item's we may use due
* to delalloc and such. outstanding_extents is the number of extent
@ -203,15 +206,10 @@ static inline bool btrfs_is_free_space_inode(struct inode *inode)
static inline int btrfs_inode_in_log(struct inode *inode, u64 generation)
{
struct btrfs_root *root = BTRFS_I(inode)->root;
int ret = 0;
mutex_lock(&root->log_mutex);
if (BTRFS_I(inode)->logged_trans == generation &&
BTRFS_I(inode)->last_sub_trans <= root->last_log_commit)
ret = 1;
mutex_unlock(&root->log_mutex);
return ret;
BTRFS_I(inode)->last_sub_trans <= BTRFS_I(inode)->last_log_commit)
return 1;
return 0;
}
#endif

2
fs/btrfs/inode.c
View file

@ -6774,6 +6774,7 @@ int btrfs_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf)
BTRFS_I(inode)->last_trans = root->fs_info->generation;
BTRFS_I(inode)->last_sub_trans = BTRFS_I(inode)->root->log_transid;
BTRFS_I(inode)->last_log_commit = BTRFS_I(inode)->root->last_log_commit;
unlock_extent_cached(io_tree, page_start, page_end, &cached_state, GFP_NOFS);
@ -7018,6 +7019,7 @@ struct inode *btrfs_alloc_inode(struct super_block *sb)
ei->csum_bytes = 0;
ei->index_cnt = (u64)-1;
ei->last_unlink_trans = 0;
ei->last_log_commit = 0;
spin_lock_init(&ei->lock);
ei->outstanding_extents = 0;

1
fs/btrfs/transaction.h
View file

@ -88,6 +88,7 @@ static inline void btrfs_set_inode_last_trans(struct btrfs_trans_handle *trans,
{
BTRFS_I(inode)->last_trans = trans->transaction->transid;
BTRFS_I(inode)->last_sub_trans = BTRFS_I(inode)->root->log_transid;
BTRFS_I(inode)->last_log_commit = BTRFS_I(inode)->root->last_log_commit;
}
int btrfs_end_transaction(struct btrfs_trans_handle *trans,

1
fs/btrfs/tree-log.c
View file

@ -3185,6 +3185,7 @@ static int btrfs_log_inode(struct btrfs_trans_handle *trans,
}
}
BTRFS_I(inode)->logged_trans = trans->transid;
BTRFS_I(inode)->last_log_commit = BTRFS_I(inode)->last_sub_trans;
out_unlock:
mutex_unlock(&BTRFS_I(inode)->log_mutex);