From aa38a711a893accf5b5192f3d705a120deaa81e0 Mon Sep 17 00:00:00 2001 From: Miao Xie Date: Fri, 18 Nov 2011 17:43:00 +0800 Subject: Btrfs: fix deadlock on metadata reservation when evicting a inode When I ran the xfstests, I found the test tasks was blocked on meta-data reservation. By debugging, I found the reason of this bug: start transaction | v reserve meta-data space | v flush delay allocation -> iput inode -> evict inode ^ | | v wait for delay allocation flush <- reserve meta-data space And besides that, the flush on evicting inode will block the thread, which is reclaiming the memory, and make oom happen easily. Fix this bug by skipping the flush step when evicting inode. Signed-off-by: Miao Xie --- fs/btrfs/extent-tree.c | 22 ++++++++++++++++++---- 1 file changed, 18 insertions(+), 4 deletions(-) (limited to 'fs/btrfs/extent-tree.c') diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c index 5d86877f10e..b7e5f6898d0 100644 --- a/fs/btrfs/extent-tree.c +++ b/fs/btrfs/extent-tree.c @@ -3887,9 +3887,9 @@ int btrfs_block_rsv_check(struct btrfs_root *root, return ret; } -int btrfs_block_rsv_refill(struct btrfs_root *root, - struct btrfs_block_rsv *block_rsv, - u64 min_reserved) +static inline int __btrfs_block_rsv_refill(struct btrfs_root *root, + struct btrfs_block_rsv *block_rsv, + u64 min_reserved, int flush) { u64 num_bytes = 0; int ret = -ENOSPC; @@ -3908,7 +3908,7 @@ int btrfs_block_rsv_refill(struct btrfs_root *root, if (!ret) return 0; - ret = reserve_metadata_bytes(root, block_rsv, num_bytes, 1); + ret = reserve_metadata_bytes(root, block_rsv, num_bytes, flush); if (!ret) { block_rsv_add_bytes(block_rsv, num_bytes, 0); return 0; @@ -3917,6 +3917,20 @@ int btrfs_block_rsv_refill(struct btrfs_root *root, return ret; } +int btrfs_block_rsv_refill(struct btrfs_root *root, + struct btrfs_block_rsv *block_rsv, + u64 min_reserved) +{ + return __btrfs_block_rsv_refill(root, block_rsv, min_reserved, 1); +} + +int btrfs_block_rsv_refill_noflush(struct btrfs_root *root, + struct btrfs_block_rsv *block_rsv, + u64 min_reserved) +{ + return __btrfs_block_rsv_refill(root, block_rsv, min_reserved, 0); +} + int btrfs_block_rsv_migrate(struct btrfs_block_rsv *src_rsv, struct btrfs_block_rsv *dst_rsv, u64 num_bytes) -- cgit v1.2.3 From 1b22bad779be7fe07242be04749ec969164528b8 Mon Sep 17 00:00:00 2001 From: Alexandre Oliva Date: Wed, 30 Nov 2011 13:43:00 -0500 Subject: Btrfs: start search for new cluster at the beginning Instead of starting at zero (offset is always zero), request a cluster starting at search_start, that denotes the beginning of the current block group. Signed-off-by: Alexandre Oliva Signed-off-by: Chris Mason --- fs/btrfs/extent-tree.c | 6 ++---- 1 file changed, 2 insertions(+), 4 deletions(-) (limited to 'fs/btrfs/extent-tree.c') diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c index b7e5f6898d0..97c12067a4b 100644 --- a/fs/btrfs/extent-tree.c +++ b/fs/btrfs/extent-tree.c @@ -5301,10 +5301,8 @@ alloc: spin_lock(&last_ptr->refill_lock); if (last_ptr->block_group && (last_ptr->block_group->ro || - !block_group_bits(last_ptr->block_group, data))) { - offset = 0; + !block_group_bits(last_ptr->block_group, data))) goto refill_cluster; - } offset = btrfs_alloc_from_cluster(block_group, last_ptr, num_bytes, search_start); @@ -5355,7 +5353,7 @@ refill_cluster: /* allocate a cluster in this block group */ ret = btrfs_find_space_cluster(trans, root, block_group, last_ptr, - offset, num_bytes, + search_start, num_bytes, empty_cluster + empty_size); if (ret == 0) { /* -- cgit v1.2.3 From 425d83156ca27f74e2cc3f370138038c3c8947f8 Mon Sep 17 00:00:00 2001 From: Alexandre Oliva Date: Wed, 30 Nov 2011 13:43:00 -0500 Subject: Btrfs: skip block groups without enough space for a cluster We test whether a block group has enough free space to hold the requested block, but when we're doing clustered allocation, we can save some cycles by testing whether it has enough room for the cluster upfront, otherwise we end up attempting to set up a cluster and failing. Only in the NO_EMPTY_SIZE loop do we attempt an unclustered allocation, and by then we'll have zeroed the cluster size, so this patch won't stop us from using the block group as a last resort. Signed-off-by: Alexandre Oliva Signed-off-by: Chris Mason --- fs/btrfs/extent-tree.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'fs/btrfs/extent-tree.c') diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c index 97c12067a4b..71c8e7049d0 100644 --- a/fs/btrfs/extent-tree.c +++ b/fs/btrfs/extent-tree.c @@ -5278,7 +5278,7 @@ alloc: spin_lock(&block_group->free_space_ctl->tree_lock); if (cached && block_group->free_space_ctl->free_space < - num_bytes + empty_size) { + num_bytes + empty_cluster + empty_size) { spin_unlock(&block_group->free_space_ctl->tree_lock); goto loop; } -- cgit v1.2.3 From be064d113906f04ea13088a8260e1e68ae0a4050 Mon Sep 17 00:00:00 2001 From: Alexandre Oliva Date: Wed, 30 Nov 2011 13:43:00 -0500 Subject: Btrfs: skip allocation attempt from empty cluster If we don't have a cluster, don't bother trying to allocate from it, jumping right away to the attempt to allocate a new cluster. Signed-off-by: Alexandre Oliva Signed-off-by: Chris Mason --- fs/btrfs/extent-tree.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) (limited to 'fs/btrfs/extent-tree.c') diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c index 71c8e7049d0..813c6bb96c9 100644 --- a/fs/btrfs/extent-tree.c +++ b/fs/btrfs/extent-tree.c @@ -5299,9 +5299,9 @@ alloc: * people trying to start a new cluster */ spin_lock(&last_ptr->refill_lock); - if (last_ptr->block_group && - (last_ptr->block_group->ro || - !block_group_bits(last_ptr->block_group, data))) + if (!last_ptr->block_group || + last_ptr->block_group->ro || + !block_group_bits(last_ptr->block_group, data)) goto refill_cluster; offset = btrfs_alloc_from_cluster(block_group, last_ptr, -- cgit v1.2.3