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Btrfs: add a delalloc mutex to inodes for delalloc reservations

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I was using i_mutex for this, but we're getting bogus lockdep warnings by doing
that and theres no real way to get rid of those, so just stop using i_mutex to
protect delalloc metadata reservations and use a delalloc mutex instead.  This
shouldn't be contended often at all, only if you are writing and mmap writing to
the file at the same time.  Thanks,

Signed-off-by: Josef Bacik <josef@redhat.com>
This commit is contained in:
Josef Bacik 2012-01-13 12:09:22 -05:00 committed by Chris Mason
parent 8c2a3ca20f
commit f248679e86
5 changed files with 7 additions and 16 deletions
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3
fs/btrfs/btrfs_inode.h
View file

@ -51,6 +51,9 @@ struct btrfs_inode {
/* held while logging the inode in tree-log.c */
struct mutex log_mutex;
/* held while doing delalloc reservations */
struct mutex delalloc_mutex;
/* used to order data wrt metadata */
struct btrfs_ordered_inode_tree ordered_tree;

5
fs/btrfs/extent-tree.c
View file

@ -4345,12 +4345,11 @@ int btrfs_delalloc_reserve_metadata(struct inode *inode, u64 num_bytes)
/* Need to be holding the i_mutex here if we aren't free space cache */
if (btrfs_is_free_space_inode(root, inode))
flush = 0;
else
WARN_ON(!mutex_is_locked(&inode->i_mutex));
if (flush && btrfs_transaction_in_commit(root->fs_info))
schedule_timeout(1);
mutex_lock(&BTRFS_I(inode)->delalloc_mutex);
num_bytes = ALIGN(num_bytes, root->sectorsize);
spin_lock(&BTRFS_I(inode)->lock);
@ -4405,6 +4404,7 @@ int btrfs_delalloc_reserve_metadata(struct inode *inode, u64 num_bytes)
btrfs_ino(inode),
to_free, 0);
}
mutex_unlock(&BTRFS_I(inode)->delalloc_mutex);
return ret;
}
@ -4415,6 +4415,7 @@ int btrfs_delalloc_reserve_metadata(struct inode *inode, u64 num_bytes)
}
BTRFS_I(inode)->reserved_extents += nr_extents;
spin_unlock(&BTRFS_I(inode)->lock);
mutex_unlock(&BTRFS_I(inode)->delalloc_mutex);
if (to_reserve)
trace_btrfs_space_reservation(root->fs_info,"delalloc",

11
fs/btrfs/inode.c
View file

@ -2239,14 +2239,7 @@ int btrfs_orphan_cleanup(struct btrfs_root *root)
continue;
}
nr_truncate++;
/*
* Need to hold the imutex for reservation purposes, not
* a huge deal here but I have a WARN_ON in
* btrfs_delalloc_reserve_space to catch offenders.
*/
mutex_lock(&inode->i_mutex);
ret = btrfs_truncate(inode);
mutex_unlock(&inode->i_mutex);
} else {
nr_unlink++;
}
@ -6411,10 +6404,7 @@ int btrfs_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf)
u64 page_start;
u64 page_end;
/* Need this to keep space reservations serialized */
mutex_lock(&inode->i_mutex);
ret = btrfs_delalloc_reserve_space(inode, PAGE_CACHE_SIZE);
mutex_unlock(&inode->i_mutex);
if (!ret)
ret = btrfs_update_time(vma->vm_file);
if (ret) {
@ -6758,6 +6748,7 @@ struct inode *btrfs_alloc_inode(struct super_block *sb)
extent_io_tree_init(&ei->io_tree, &inode->i_data);
extent_io_tree_init(&ei->io_failure_tree, &inode->i_data);
mutex_init(&ei->log_mutex);
mutex_init(&ei->delalloc_mutex);
btrfs_ordered_inode_tree_init(&ei->ordered_tree);
INIT_LIST_HEAD(&ei->i_orphan);
INIT_LIST_HEAD(&ei->delalloc_inodes);

2
fs/btrfs/ioctl.c
View file

@ -868,10 +868,8 @@ static int cluster_pages_for_defrag(struct inode *inode,
return 0;
file_end = (isize - 1) >> PAGE_CACHE_SHIFT;
mutex_lock(&inode->i_mutex);
ret = btrfs_delalloc_reserve_space(inode,
num_pages << PAGE_CACHE_SHIFT);
mutex_unlock(&inode->i_mutex);
if (ret)
return ret;
again:

2
fs/btrfs/relocation.c
View file

@ -2949,9 +2949,7 @@ static int relocate_file_extent_cluster(struct inode *inode,
index = (cluster->start - offset) >> PAGE_CACHE_SHIFT;
last_index = (cluster->end - offset) >> PAGE_CACHE_SHIFT;
while (index <= last_index) {
mutex_lock(&inode->i_mutex);
ret = btrfs_delalloc_reserve_metadata(inode, PAGE_CACHE_SIZE);
mutex_unlock(&inode->i_mutex);
if (ret)
goto out;