| Message ID | 1488919266-17006-1-git-send-email-fdmanana@kernel.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Tue, Mar 07, 2017 at 08:41:06PM +0000, fdmanana@kernel.org wrote: > From: Filipe Manana <fdmanana@suse.com> > > When attempting to COW a file range (we are starting writeback and doing > COW), if we manage to reserve an extent for the range we will write into > but fail after reserving it and before creating the respective ordered > extent, we end up in an error path where we attempt to decrement the > data space's bytes_may_use counter after we already did it while > reserving the extent, leading to a warning/trace like the following: > > [ 847.621524] ------------[ cut here ]------------ > [ 847.625441] WARNING: CPU: 5 PID: 4905 at fs/btrfs/extent-tree.c:4316 btrfs_free_reserved_data_space_noquota+0x60/0x9f [btrfs] > [ 847.633704] Modules linked in: btrfs crc32c_generic xor raid6_pq acpi_cpufreq i2c_piix4 ppdev psmouse tpm_tis serio_raw pcspkr parport_pc tpm_tis_core i2c_core sg > [ 847.644616] CPU: 5 PID: 4905 Comm: xfs_io Not tainted 4.10.0-rc8-btrfs-next-37+ #2 > [ 847.648601] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.9.1-0-gb3ef39f-prebuilt.qemu-project.org 04/01/2014 > [ 847.648601] Call Trace: > [ 847.648601] dump_stack+0x67/0x90 > [ 847.648601] __warn+0xc2/0xdd > [ 847.648601] warn_slowpath_null+0x1d/0x1f > [ 847.648601] btrfs_free_reserved_data_space_noquota+0x60/0x9f [btrfs] > [ 847.648601] btrfs_clear_bit_hook+0x140/0x258 [btrfs] > [ 847.648601] clear_state_bit+0x87/0x128 [btrfs] > [ 847.648601] __clear_extent_bit+0x222/0x2b7 [btrfs] > [ 847.648601] clear_extent_bit+0x17/0x19 [btrfs] > [ 847.648601] extent_clear_unlock_delalloc+0x3b/0x6b [btrfs] > [ 847.648601] cow_file_range.isra.39+0x387/0x39a [btrfs] > [ 847.648601] run_delalloc_nocow+0x4d7/0x70e [btrfs] > [ 847.648601] ? arch_local_irq_save+0x9/0xc > [ 847.648601] run_delalloc_range+0xa7/0x2b5 [btrfs] > [ 847.648601] writepage_delalloc.isra.31+0xb9/0x15c [btrfs] > [ 847.648601] __extent_writepage+0x249/0x2e8 [btrfs] > [ 847.648601] extent_write_cache_pages.constprop.33+0x28b/0x36c [btrfs] > [ 847.648601] ? arch_local_irq_save+0x9/0xc > [ 847.648601] ? mark_lock+0x24/0x201 > [ 847.648601] extent_writepages+0x4b/0x5c [btrfs] > [ 847.648601] ? btrfs_writepage_start_hook+0xed/0xed [btrfs] > [ 847.648601] btrfs_writepages+0x28/0x2a [btrfs] > [ 847.648601] do_writepages+0x23/0x2c > [ 847.648601] __filemap_fdatawrite_range+0x5a/0x61 > [ 847.648601] filemap_fdatawrite_range+0x13/0x15 > [ 847.648601] btrfs_fdatawrite_range+0x20/0x46 [btrfs] > [ 847.648601] start_ordered_ops+0x19/0x23 [btrfs] > [ 847.648601] btrfs_sync_file+0x136/0x42c [btrfs] > [ 847.648601] vfs_fsync_range+0x8c/0x9e > [ 847.648601] vfs_fsync+0x1c/0x1e > [ 847.648601] do_fsync+0x31/0x4a > [ 847.648601] SyS_fsync+0x10/0x14 > [ 847.648601] entry_SYSCALL_64_fastpath+0x18/0xad > [ 847.648601] RIP: 0033:0x7f5b05200800 > [ 847.648601] RSP: 002b:00007ffe204f71c8 EFLAGS: 00000246 ORIG_RAX: 000000000000004a > [ 847.648601] RAX: ffffffffffffffda RBX: ffffffff8109637b RCX: 00007f5b05200800 > [ 847.648601] RDX: 00000000008bd0a0 RSI: 00000000008bd2e0 RDI: 0000000000000003 > [ 847.648601] RBP: ffffc90001d67f98 R08: 000000000000ffff R09: 000000000000001f > [ 847.648601] R10: 00000000000001f6 R11: 0000000000000246 R12: 0000000000000046 > [ 847.648601] R13: ffffc90001d67f78 R14: 00007f5b054be740 R15: 00007f5b054be740 > [ 847.648601] ? trace_hardirqs_off_caller+0x3f/0xaa > [ 847.685787] ---[ end trace 2a4a3e15382508e8 ]--- > > So fix this by not attempting to decrement the data space info's > bytes_may_use counter if we already reserved the extent and an error > happened before creating the ordered extent. We are already correctly > freeing the reserved extent if an error happens, so there's no additional > measure needed. > Reviewed-by: Liu Bo <bo.li.liu@oracle.com> Thanks, -liubo > Signed-off-by: Filipe Manana <fdmanana@suse.com> > --- > > V2: Removed previous dependence on a no longer needed cleanup patch and > rebased it on top of Qu's recent patchset that fixes hanging ordered > extents when errors happen. > > V3: Simplified extent flags used for freeing reserved metadata and data. > > fs/btrfs/extent_io.h | 4 +++- > fs/btrfs/inode.c | 59 +++++++++++++++++++++++++++++++++++++--------------- > 2 files changed, 45 insertions(+), 18 deletions(-) > > diff --git a/fs/btrfs/extent_io.h b/fs/btrfs/extent_io.h > index 3e4fad4..48a30d0 100644 > --- a/fs/btrfs/extent_io.h > +++ b/fs/btrfs/extent_io.h > @@ -14,7 +14,7 @@ > #define EXTENT_DEFRAG (1U << 6) > #define EXTENT_BOUNDARY (1U << 9) > #define EXTENT_NODATASUM (1U << 10) > -#define EXTENT_DO_ACCOUNTING (1U << 11) > +#define EXTENT_CLEAR_META_RESV (1U << 11) > #define EXTENT_FIRST_DELALLOC (1U << 12) > #define EXTENT_NEED_WAIT (1U << 13) > #define EXTENT_DAMAGED (1U << 14) > @@ -22,6 +22,8 @@ > #define EXTENT_QGROUP_RESERVED (1U << 16) > #define EXTENT_CLEAR_DATA_RESV (1U << 17) > #define EXTENT_IOBITS (EXTENT_LOCKED | EXTENT_WRITEBACK) > +#define EXTENT_DO_ACCOUNTING (EXTENT_CLEAR_META_RESV | \ > + EXTENT_CLEAR_DATA_RESV) > #define EXTENT_CTLBITS (EXTENT_DO_ACCOUNTING | EXTENT_FIRST_DELALLOC) > > /* > diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c > index 9b03eb9b..c8ce47a 100644 > --- a/fs/btrfs/inode.c > +++ b/fs/btrfs/inode.c > @@ -942,10 +942,13 @@ static noinline int cow_file_range(struct inode *inode, > u64 num_bytes; > unsigned long ram_size; > u64 disk_num_bytes; > - u64 cur_alloc_size; > + u64 cur_alloc_size = 0; > u64 blocksize = fs_info->sectorsize; > struct btrfs_key ins; > struct extent_map *em; > + unsigned clear_bits; > + unsigned long page_ops; > + bool extent_reserved = false; > int ret = 0; > > if (btrfs_is_free_space_inode(BTRFS_I(inode))) { > @@ -990,14 +993,14 @@ static noinline int cow_file_range(struct inode *inode, > start + num_bytes - 1, 0); > > while (disk_num_bytes > 0) { > - unsigned long op; > - > cur_alloc_size = disk_num_bytes; > ret = btrfs_reserve_extent(root, cur_alloc_size, cur_alloc_size, > fs_info->sectorsize, 0, alloc_hint, > &ins, 1, 1); > if (ret < 0) > goto out_unlock; > + cur_alloc_size = ins.offset; > + extent_reserved = true; > > ram_size = ins.offset; > em = create_io_em(inode, start, ins.offset, /* len */ > @@ -1012,7 +1015,6 @@ static noinline int cow_file_range(struct inode *inode, > goto out_reserve; > free_extent_map(em); > > - cur_alloc_size = ins.offset; > ret = btrfs_add_ordered_extent(inode, start, ins.objectid, > ram_size, cur_alloc_size, 0); > if (ret) > @@ -1047,14 +1049,14 @@ static noinline int cow_file_range(struct inode *inode, > * Do set the Private2 bit so we know this page was properly > * setup for writepage > */ > - op = unlock ? PAGE_UNLOCK : 0; > - op |= PAGE_SET_PRIVATE2; > + page_ops = unlock ? PAGE_UNLOCK : 0; > + page_ops |= PAGE_SET_PRIVATE2; > > extent_clear_unlock_delalloc(inode, start, > start + ram_size - 1, > delalloc_end, locked_page, > EXTENT_LOCKED | EXTENT_DELALLOC, > - op); > + page_ops); > if (disk_num_bytes > cur_alloc_size) > disk_num_bytes = 0; > else > @@ -1062,6 +1064,7 @@ static noinline int cow_file_range(struct inode *inode, > num_bytes -= cur_alloc_size; > alloc_hint = ins.objectid + ins.offset; > start += cur_alloc_size; > + extent_reserved = false; > > /* > * btrfs_reloc_clone_csums() error, since start is increased > @@ -1080,12 +1083,35 @@ static noinline int cow_file_range(struct inode *inode, > btrfs_dec_block_group_reservations(fs_info, ins.objectid); > btrfs_free_reserved_extent(fs_info, ins.objectid, ins.offset, 1); > out_unlock: > + clear_bits = EXTENT_LOCKED | EXTENT_DELALLOC | EXTENT_DEFRAG | > + EXTENT_CLEAR_META_RESV; > + page_ops = PAGE_UNLOCK | PAGE_CLEAR_DIRTY | PAGE_SET_WRITEBACK | > + PAGE_END_WRITEBACK; > + /* > + * If we reserved an extent for our delalloc range (or a subrange) and > + * failed to create the respective ordered extent, then it means that > + * when we reserved the extent we decremented the extent's size from > + * the data space_info's bytes_may_use counter and incremented the > + * space_info's bytes_reserved counter by the same amount. We must make > + * sure extent_clear_unlock_delalloc() does not try to decrement again > + * the data space_info's bytes_may_use counter, therefore we do not pass > + * it the flag EXTENT_CLEAR_DATA_RESV. > + */ > + if (extent_reserved) { > + extent_clear_unlock_delalloc(inode, start, > + start + cur_alloc_size, > + start + cur_alloc_size, > + locked_page, > + clear_bits, > + page_ops); > + start += cur_alloc_size; > + if (start >= end) > + goto out; > + } > extent_clear_unlock_delalloc(inode, start, end, delalloc_end, > locked_page, > - EXTENT_LOCKED | EXTENT_DO_ACCOUNTING | > - EXTENT_DELALLOC | EXTENT_DEFRAG, > - PAGE_UNLOCK | PAGE_CLEAR_DIRTY | > - PAGE_SET_WRITEBACK | PAGE_END_WRITEBACK); > + clear_bits | EXTENT_CLEAR_DATA_RESV, > + page_ops); > goto out; > } > > @@ -1775,7 +1801,7 @@ static void btrfs_clear_bit_hook(struct btrfs_inode *inode, > > if (*bits & EXTENT_FIRST_DELALLOC) { > *bits &= ~EXTENT_FIRST_DELALLOC; > - } else if (!(*bits & EXTENT_DO_ACCOUNTING)) { > + } else if (!(*bits & EXTENT_CLEAR_META_RESV)) { > spin_lock(&inode->lock); > inode->outstanding_extents -= num_extents; > spin_unlock(&inode->lock); > @@ -1786,7 +1812,7 @@ static void btrfs_clear_bit_hook(struct btrfs_inode *inode, > * don't need to call dellalloc_release_metadata if there is an > * error. > */ > - if (*bits & EXTENT_DO_ACCOUNTING && > + if (*bits & EXTENT_CLEAR_META_RESV && > root != fs_info->tree_root) > btrfs_delalloc_release_metadata(inode, len); > > @@ -1794,10 +1820,9 @@ static void btrfs_clear_bit_hook(struct btrfs_inode *inode, > if (btrfs_is_testing(fs_info)) > return; > > - if (root->root_key.objectid != BTRFS_DATA_RELOC_TREE_OBJECTID > - && do_list && !(state->state & EXTENT_NORESERVE) > - && (*bits & (EXTENT_DO_ACCOUNTING | > - EXTENT_CLEAR_DATA_RESV))) > + if (root->root_key.objectid != BTRFS_DATA_RELOC_TREE_OBJECTID && > + do_list && !(state->state & EXTENT_NORESERVE) && > + (*bits & EXTENT_CLEAR_DATA_RESV)) > btrfs_free_reserved_data_space_noquota( > &inode->vfs_inode, > state->start, len); > -- > 2.7.0.rc3 > > -- > To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/fs/btrfs/extent_io.h b/fs/btrfs/extent_io.h index 3e4fad4..48a30d0 100644 --- a/fs/btrfs/extent_io.h +++ b/fs/btrfs/extent_io.h @@ -14,7 +14,7 @@ #define EXTENT_DEFRAG (1U << 6) #define EXTENT_BOUNDARY (1U << 9) #define EXTENT_NODATASUM (1U << 10) -#define EXTENT_DO_ACCOUNTING (1U << 11) +#define EXTENT_CLEAR_META_RESV (1U << 11) #define EXTENT_FIRST_DELALLOC (1U << 12) #define EXTENT_NEED_WAIT (1U << 13) #define EXTENT_DAMAGED (1U << 14) @@ -22,6 +22,8 @@ #define EXTENT_QGROUP_RESERVED (1U << 16) #define EXTENT_CLEAR_DATA_RESV (1U << 17) #define EXTENT_IOBITS (EXTENT_LOCKED | EXTENT_WRITEBACK) +#define EXTENT_DO_ACCOUNTING (EXTENT_CLEAR_META_RESV | \ + EXTENT_CLEAR_DATA_RESV) #define EXTENT_CTLBITS (EXTENT_DO_ACCOUNTING | EXTENT_FIRST_DELALLOC) /* diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c index 9b03eb9b..c8ce47a 100644 --- a/fs/btrfs/inode.c +++ b/fs/btrfs/inode.c @@ -942,10 +942,13 @@ static noinline int cow_file_range(struct inode *inode, u64 num_bytes; unsigned long ram_size; u64 disk_num_bytes; - u64 cur_alloc_size; + u64 cur_alloc_size = 0; u64 blocksize = fs_info->sectorsize; struct btrfs_key ins; struct extent_map *em; + unsigned clear_bits; + unsigned long page_ops; + bool extent_reserved = false; int ret = 0; if (btrfs_is_free_space_inode(BTRFS_I(inode))) { @@ -990,14 +993,14 @@ static noinline int cow_file_range(struct inode *inode, start + num_bytes - 1, 0); while (disk_num_bytes > 0) { - unsigned long op; - cur_alloc_size = disk_num_bytes; ret = btrfs_reserve_extent(root, cur_alloc_size, cur_alloc_size, fs_info->sectorsize, 0, alloc_hint, &ins, 1, 1); if (ret < 0) goto out_unlock; + cur_alloc_size = ins.offset; + extent_reserved = true; ram_size = ins.offset; em = create_io_em(inode, start, ins.offset, /* len */ @@ -1012,7 +1015,6 @@ static noinline int cow_file_range(struct inode *inode, goto out_reserve; free_extent_map(em); - cur_alloc_size = ins.offset; ret = btrfs_add_ordered_extent(inode, start, ins.objectid, ram_size, cur_alloc_size, 0); if (ret) @@ -1047,14 +1049,14 @@ static noinline int cow_file_range(struct inode *inode, * Do set the Private2 bit so we know this page was properly * setup for writepage */ - op = unlock ? PAGE_UNLOCK : 0; - op |= PAGE_SET_PRIVATE2; + page_ops = unlock ? PAGE_UNLOCK : 0; + page_ops |= PAGE_SET_PRIVATE2; extent_clear_unlock_delalloc(inode, start, start + ram_size - 1, delalloc_end, locked_page, EXTENT_LOCKED | EXTENT_DELALLOC, - op); + page_ops); if (disk_num_bytes > cur_alloc_size) disk_num_bytes = 0; else @@ -1062,6 +1064,7 @@ static noinline int cow_file_range(struct inode *inode, num_bytes -= cur_alloc_size; alloc_hint = ins.objectid + ins.offset; start += cur_alloc_size; + extent_reserved = false; /* * btrfs_reloc_clone_csums() error, since start is increased @@ -1080,12 +1083,35 @@ static noinline int cow_file_range(struct inode *inode, btrfs_dec_block_group_reservations(fs_info, ins.objectid); btrfs_free_reserved_extent(fs_info, ins.objectid, ins.offset, 1); out_unlock: + clear_bits = EXTENT_LOCKED | EXTENT_DELALLOC | EXTENT_DEFRAG | + EXTENT_CLEAR_META_RESV; + page_ops = PAGE_UNLOCK | PAGE_CLEAR_DIRTY | PAGE_SET_WRITEBACK | + PAGE_END_WRITEBACK; + /* + * If we reserved an extent for our delalloc range (or a subrange) and + * failed to create the respective ordered extent, then it means that + * when we reserved the extent we decremented the extent's size from + * the data space_info's bytes_may_use counter and incremented the + * space_info's bytes_reserved counter by the same amount. We must make + * sure extent_clear_unlock_delalloc() does not try to decrement again + * the data space_info's bytes_may_use counter, therefore we do not pass + * it the flag EXTENT_CLEAR_DATA_RESV. + */ + if (extent_reserved) { + extent_clear_unlock_delalloc(inode, start, + start + cur_alloc_size, + start + cur_alloc_size, + locked_page, + clear_bits, + page_ops); + start += cur_alloc_size; + if (start >= end) + goto out; + } extent_clear_unlock_delalloc(inode, start, end, delalloc_end, locked_page, - EXTENT_LOCKED | EXTENT_DO_ACCOUNTING | - EXTENT_DELALLOC | EXTENT_DEFRAG, - PAGE_UNLOCK | PAGE_CLEAR_DIRTY | - PAGE_SET_WRITEBACK | PAGE_END_WRITEBACK); + clear_bits | EXTENT_CLEAR_DATA_RESV, + page_ops); goto out; } @@ -1775,7 +1801,7 @@ static void btrfs_clear_bit_hook(struct btrfs_inode *inode, if (*bits & EXTENT_FIRST_DELALLOC) { *bits &= ~EXTENT_FIRST_DELALLOC; - } else if (!(*bits & EXTENT_DO_ACCOUNTING)) { + } else if (!(*bits & EXTENT_CLEAR_META_RESV)) { spin_lock(&inode->lock); inode->outstanding_extents -= num_extents; spin_unlock(&inode->lock); @@ -1786,7 +1812,7 @@ static void btrfs_clear_bit_hook(struct btrfs_inode *inode, * don't need to call dellalloc_release_metadata if there is an * error. */ - if (*bits & EXTENT_DO_ACCOUNTING && + if (*bits & EXTENT_CLEAR_META_RESV && root != fs_info->tree_root) btrfs_delalloc_release_metadata(inode, len); @@ -1794,10 +1820,9 @@ static void btrfs_clear_bit_hook(struct btrfs_inode *inode, if (btrfs_is_testing(fs_info)) return; - if (root->root_key.objectid != BTRFS_DATA_RELOC_TREE_OBJECTID - && do_list && !(state->state & EXTENT_NORESERVE) - && (*bits & (EXTENT_DO_ACCOUNTING | - EXTENT_CLEAR_DATA_RESV))) + if (root->root_key.objectid != BTRFS_DATA_RELOC_TREE_OBJECTID && + do_list && !(state->state & EXTENT_NORESERVE) && + (*bits & EXTENT_CLEAR_DATA_RESV)) btrfs_free_reserved_data_space_noquota( &inode->vfs_inode, state->start, len);