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 5d86877f10e1..b7e5f6898d07 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 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 b7e5f6898d07..97c12067a4b0 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 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 97c12067a4b0..71c8e7049d0c 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 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 71c8e7049d0c..813c6bb96c9a 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 From 062c05c46bd4358aad7a0e0cb5ffeb98ab935286 Mon Sep 17 00:00:00 2001 From: Alexandre Oliva Date: Wed, 7 Dec 2011 19:50:42 -0500 Subject: Btrfs: try to allocate from cluster even at LOOP_NO_EMPTY_SIZE If we reach LOOP_NO_EMPTY_SIZE, we won't even try to use a cluster that others might have set up. Odds are that there won't be one, but if someone else succeeded in setting it up, we might as well use it, even if we don't try to set up a cluster again. Signed-off-by: Alexandre Oliva Signed-off-by: Chris Mason --- fs/btrfs/extent-tree.c | 26 ++++++++++++++++++-------- 1 file changed, 18 insertions(+), 8 deletions(-) (limited to 'fs/btrfs/extent-tree.c') diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c index 813c6bb96c9a..db0b23b14f20 100644 --- a/fs/btrfs/extent-tree.c +++ b/fs/btrfs/extent-tree.c @@ -5285,15 +5285,10 @@ alloc: spin_unlock(&block_group->free_space_ctl->tree_lock); /* - * Ok we want to try and use the cluster allocator, so lets look - * there, unless we are on LOOP_NO_EMPTY_SIZE, since we will - * have tried the cluster allocator plenty of times at this - * point and not have found anything, so we are likely way too - * fragmented for the clustering stuff to find anything, so lets - * just skip it and let the allocator find whatever block it can - * find + * Ok we want to try and use the cluster allocator, so + * lets look there */ - if (last_ptr && loop < LOOP_NO_EMPTY_SIZE) { + if (last_ptr) { /* * the refill lock keeps out other * people trying to start a new cluster @@ -5342,6 +5337,20 @@ alloc: } spin_unlock(&last_ptr->lock); refill_cluster: + /* If we are on LOOP_NO_EMPTY_SIZE, we can't + * set up a new clusters, so lets just skip it + * and let the allocator find whatever block + * it can find. If we reach this point, we + * will have tried the cluster allocator + * plenty of times and not have found + * anything, so we are likely way too + * fragmented for the clustering stuff to find + * anything. */ + if (loop >= LOOP_NO_EMPTY_SIZE) { + spin_unlock(&last_ptr->refill_lock); + goto unclustered_alloc; + } + /* * this cluster didn't work out, free it and * start over @@ -5389,6 +5398,7 @@ refill_cluster: goto loop; } +unclustered_alloc: offset = btrfs_find_space_for_alloc(block_group, search_start, num_bytes, empty_size); /* -- cgit From 274bd4fb3ed6b72c1d77ef8850511f09fc6b8e4d Mon Sep 17 00:00:00 2001 From: Alexandre Oliva Date: Wed, 7 Dec 2011 20:08:40 -0500 Subject: Btrfs: try cluster but don't advance in search list When we find an existing cluster, we switch to its block group as the current block group, possibly skipping multiple blocks in the process. Furthermore, under heavy contention, multiple threads may fail to allocate from a cluster and then release just-created clusters just to proceed to create new ones in a different block group. This patch tries to allocate from an existing cluster regardless of its block group, and doesn't switch to that group, instead proceeding to try to allocate a cluster from the group it was iterating before the attempt. Signed-off-by: Alexandre Oliva Signed-off-by: Chris Mason --- fs/btrfs/extent-tree.c | 74 +++++++++++++++++++++----------------------------- 1 file changed, 31 insertions(+), 43 deletions(-) (limited to 'fs/btrfs/extent-tree.c') diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c index db0b23b14f20..05e1386b8bec 100644 --- a/fs/btrfs/extent-tree.c +++ b/fs/btrfs/extent-tree.c @@ -5106,11 +5106,11 @@ static noinline int find_free_extent(struct btrfs_trans_handle *trans, struct btrfs_root *root = orig_root->fs_info->extent_root; struct btrfs_free_cluster *last_ptr = NULL; struct btrfs_block_group_cache *block_group = NULL; + struct btrfs_block_group_cache *used_block_group; int empty_cluster = 2 * 1024 * 1024; int allowed_chunk_alloc = 0; int done_chunk_alloc = 0; struct btrfs_space_info *space_info; - int last_ptr_loop = 0; int loop = 0; int index = 0; int alloc_type = (data & BTRFS_BLOCK_GROUP_DATA) ? @@ -5172,6 +5172,7 @@ static noinline int find_free_extent(struct btrfs_trans_handle *trans, ideal_cache: block_group = btrfs_lookup_block_group(root->fs_info, search_start); + used_block_group = block_group; /* * we don't want to use the block group if it doesn't match our * allocation bits, or if its not cached. @@ -5209,6 +5210,7 @@ search: u64 offset; int cached; + used_block_group = block_group; btrfs_get_block_group(block_group); search_start = block_group->key.objectid; @@ -5294,49 +5296,33 @@ 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)) + used_block_group = last_ptr->block_group; + if (used_block_group != block_group && + (!used_block_group || + used_block_group->ro || + !block_group_bits(used_block_group, data))) { + used_block_group = block_group; goto refill_cluster; + } + + if (used_block_group != block_group) + btrfs_get_block_group(used_block_group); - offset = btrfs_alloc_from_cluster(block_group, last_ptr, - num_bytes, search_start); + offset = btrfs_alloc_from_cluster(used_block_group, + last_ptr, num_bytes, used_block_group->key.objectid); if (offset) { /* we have a block, we're done */ spin_unlock(&last_ptr->refill_lock); goto checks; } - spin_lock(&last_ptr->lock); - /* - * whoops, this cluster doesn't actually point to - * this block group. Get a ref on the block - * group is does point to and try again - */ - if (!last_ptr_loop && last_ptr->block_group && - last_ptr->block_group != block_group && - index <= - get_block_group_index(last_ptr->block_group)) { - - btrfs_put_block_group(block_group); - block_group = last_ptr->block_group; - btrfs_get_block_group(block_group); - spin_unlock(&last_ptr->lock); - spin_unlock(&last_ptr->refill_lock); - - last_ptr_loop = 1; - search_start = block_group->key.objectid; - /* - * we know this block group is properly - * in the list because - * btrfs_remove_block_group, drops the - * cluster before it removes the block - * group from the list - */ - goto have_block_group; + WARN_ON(last_ptr->block_group != used_block_group); + if (used_block_group != block_group) { + btrfs_put_block_group(used_block_group); + used_block_group = block_group; } - spin_unlock(&last_ptr->lock); refill_cluster: + BUG_ON(used_block_group != block_group); /* If we are on LOOP_NO_EMPTY_SIZE, we can't * set up a new clusters, so lets just skip it * and let the allocator find whatever block @@ -5357,8 +5343,6 @@ refill_cluster: */ btrfs_return_cluster_to_free_space(NULL, last_ptr); - last_ptr_loop = 0; - /* allocate a cluster in this block group */ ret = btrfs_find_space_cluster(trans, root, block_group, last_ptr, @@ -5425,14 +5409,14 @@ checks: search_start = stripe_align(root, offset); /* move on to the next group */ if (search_start + num_bytes >= search_end) { - btrfs_add_free_space(block_group, offset, num_bytes); + btrfs_add_free_space(used_block_group, offset, num_bytes); goto loop; } /* move on to the next group */ if (search_start + num_bytes > - block_group->key.objectid + block_group->key.offset) { - btrfs_add_free_space(block_group, offset, num_bytes); + used_block_group->key.objectid + used_block_group->key.offset) { + btrfs_add_free_space(used_block_group, offset, num_bytes); goto loop; } @@ -5440,14 +5424,14 @@ checks: ins->offset = num_bytes; if (offset < search_start) - btrfs_add_free_space(block_group, offset, + btrfs_add_free_space(used_block_group, offset, search_start - offset); BUG_ON(offset > search_start); - ret = btrfs_update_reserved_bytes(block_group, num_bytes, + ret = btrfs_update_reserved_bytes(used_block_group, num_bytes, alloc_type); if (ret == -EAGAIN) { - btrfs_add_free_space(block_group, offset, num_bytes); + btrfs_add_free_space(used_block_group, offset, num_bytes); goto loop; } @@ -5456,15 +5440,19 @@ checks: ins->offset = num_bytes; if (offset < search_start) - btrfs_add_free_space(block_group, offset, + btrfs_add_free_space(used_block_group, offset, search_start - offset); BUG_ON(offset > search_start); + if (used_block_group != block_group) + btrfs_put_block_group(used_block_group); btrfs_put_block_group(block_group); break; loop: failed_cluster_refill = false; failed_alloc = false; BUG_ON(index != get_block_group_index(block_group)); + if (used_block_group != block_group) + btrfs_put_block_group(used_block_group); btrfs_put_block_group(block_group); } up_read(&space_info->groups_sem); -- cgit From 660d3f6cde552323578b85fc5a09a6742f1fe804 Mon Sep 17 00:00:00 2001 From: Josef Bacik Date: Fri, 9 Dec 2011 11:18:51 -0500 Subject: Btrfs: fix how we do delalloc reservations and how we free reservations on error Running xfstests 269 with some tracing my scripts kept spitting out errors about releasing bytes that we didn't actually have reserved. This took me down a huge rabbit hole and it turns out the way we deal with reserved_extents is wrong, we need to only be setting it if the reservation succeeds, otherwise the free() method will come in and unreserve space that isn't actually reserved yet, which can lead to other warnings and such. The math was all working out right in the end, but it caused all sorts of other issues in addition to making my scripts yell and scream and generally make it impossible for me to track down the original issue I was looking for. The other problem is with our error handling in the reservation code. There are two cases that we need to deal with 1) We raced with free. In this case free won't free anything because csum_bytes is modified before we dro the lock in our reservation path, so free rightly doesn't release any space because the reservation code may be depending on that reservation. However if we fail, we need the reservation side to do the free at that point since that space is no longer in use. So as it stands the code was doing this fine and it worked out, except in case #2 2) We don't race with free. Nobody comes in and changes anything, and our reservation fails. In this case we didn't reserve anything anyway and we just need to clean up csum_bytes but not free anything. So we keep track of csum_bytes before we drop the lock and if it hasn't changed we know we can just decrement csum_bytes and carry on. Because of the case where we can race with free()'s since we have to drop our spin_lock to do the reservation, I'm going to serialize all reservations with the i_mutex. We already get this for free in the heavy use paths, truncate and file write all hold the i_mutex, just needed to add it to page_mkwrite and various ioctl/balance things. With this patch my space leak scripts no longer scream bloody murder. Thanks, Signed-off-by: Josef Bacik --- fs/btrfs/extent-tree.c | 43 ++++++++++++++++++++++++++++++------------- fs/btrfs/inode.c | 10 ++++++++++ fs/btrfs/ioctl.c | 2 ++ fs/btrfs/relocation.c | 2 ++ 4 files changed, 44 insertions(+), 13 deletions(-) (limited to 'fs/btrfs/extent-tree.c') diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c index 05e1386b8bec..4eb4d2748bec 100644 --- a/fs/btrfs/extent-tree.c +++ b/fs/btrfs/extent-tree.c @@ -4203,12 +4203,17 @@ int btrfs_delalloc_reserve_metadata(struct inode *inode, u64 num_bytes) struct btrfs_root *root = BTRFS_I(inode)->root; struct btrfs_block_rsv *block_rsv = &root->fs_info->delalloc_block_rsv; u64 to_reserve = 0; + u64 csum_bytes; unsigned nr_extents = 0; + int extra_reserve = 0; int flush = 1; int ret; + /* 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); @@ -4219,11 +4224,9 @@ int btrfs_delalloc_reserve_metadata(struct inode *inode, u64 num_bytes) BTRFS_I(inode)->outstanding_extents++; if (BTRFS_I(inode)->outstanding_extents > - BTRFS_I(inode)->reserved_extents) { + BTRFS_I(inode)->reserved_extents) nr_extents = BTRFS_I(inode)->outstanding_extents - BTRFS_I(inode)->reserved_extents; - BTRFS_I(inode)->reserved_extents += nr_extents; - } /* * Add an item to reserve for updating the inode when we complete the @@ -4231,11 +4234,12 @@ int btrfs_delalloc_reserve_metadata(struct inode *inode, u64 num_bytes) */ if (!BTRFS_I(inode)->delalloc_meta_reserved) { nr_extents++; - BTRFS_I(inode)->delalloc_meta_reserved = 1; + extra_reserve = 1; } to_reserve = btrfs_calc_trans_metadata_size(root, nr_extents); to_reserve += calc_csum_metadata_size(inode, num_bytes, 1); + csum_bytes = BTRFS_I(inode)->csum_bytes; spin_unlock(&BTRFS_I(inode)->lock); ret = reserve_metadata_bytes(root, block_rsv, to_reserve, flush); @@ -4245,22 +4249,35 @@ int btrfs_delalloc_reserve_metadata(struct inode *inode, u64 num_bytes) spin_lock(&BTRFS_I(inode)->lock); dropped = drop_outstanding_extent(inode); - to_free = calc_csum_metadata_size(inode, num_bytes, 0); - spin_unlock(&BTRFS_I(inode)->lock); - to_free += btrfs_calc_trans_metadata_size(root, dropped); - /* - * Somebody could have come in and twiddled with the - * reservation, so if we have to free more than we would have - * reserved from this reservation go ahead and release those - * bytes. + * If the inodes csum_bytes is the same as the original + * csum_bytes then we know we haven't raced with any free()ers + * so we can just reduce our inodes csum bytes and carry on. + * Otherwise we have to do the normal free thing to account for + * the case that the free side didn't free up its reserve + * because of this outstanding reservation. */ - to_free -= to_reserve; + if (BTRFS_I(inode)->csum_bytes == csum_bytes) + calc_csum_metadata_size(inode, num_bytes, 0); + else + to_free = calc_csum_metadata_size(inode, num_bytes, 0); + spin_unlock(&BTRFS_I(inode)->lock); + if (dropped) + to_free += btrfs_calc_trans_metadata_size(root, dropped); + if (to_free) btrfs_block_rsv_release(root, block_rsv, to_free); return ret; } + spin_lock(&BTRFS_I(inode)->lock); + if (extra_reserve) { + BTRFS_I(inode)->delalloc_meta_reserved = 1; + nr_extents--; + } + BTRFS_I(inode)->reserved_extents += nr_extents; + spin_unlock(&BTRFS_I(inode)->lock); + block_rsv_add_bytes(block_rsv, to_reserve, 1); return 0; diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c index eec33b9c953d..8938174e6bc1 100644 --- a/fs/btrfs/inode.c +++ b/fs/btrfs/inode.c @@ -2192,7 +2192,14 @@ 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++; } @@ -6342,7 +6349,10 @@ 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) { diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c index 72d461656f60..dd8891662355 100644 --- a/fs/btrfs/ioctl.c +++ b/fs/btrfs/ioctl.c @@ -858,8 +858,10 @@ 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: diff --git a/fs/btrfs/relocation.c b/fs/btrfs/relocation.c index dff29d5e151a..cfb55434a469 100644 --- a/fs/btrfs/relocation.c +++ b/fs/btrfs/relocation.c @@ -2947,7 +2947,9 @@ 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; -- cgit From e65cbb94e036058128a5dec6398be2fd64cf88ba Mon Sep 17 00:00:00 2001 From: Josef Bacik Date: Tue, 13 Dec 2011 16:04:54 -0500 Subject: Btrfs: only set cache_generation if we setup the block group A user reported a problem booting into a new kernel with the old format inodes. He was panicing in cow_file_range while writing out the inode cache. This is because if the block group is not cached we'll just skip writing out the cache, however if it gets dirtied again in the same transaction and it finished caching we'd go ahead and write it out, but since we set cache_generation to the transid we think we've already truncated it and will just carry on, running into cow_file_range and blowing up. We need to make sure we only set cache_generation if we've done the truncate. The user tested this patch and verified that the panic no longer occured. Thanks, Reported-and-Tested-by: Klaus Bitto Signed-off-by: Josef Bacik --- 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 4eb4d2748bec..8603ee4e3dfd 100644 --- a/fs/btrfs/extent-tree.c +++ b/fs/btrfs/extent-tree.c @@ -2822,7 +2822,7 @@ out_free: btrfs_release_path(path); out: spin_lock(&block_group->lock); - if (!ret) + if (!ret && dcs == BTRFS_DC_SETUP) block_group->cache_generation = trans->transid; block_group->disk_cache_state = dcs; spin_unlock(&block_group->lock); -- cgit