From 7e9620f21d8c9e389fd6845487e07d5df898a2e4 Mon Sep 17 00:00:00 2001 From: Dave Chinner Date: Mon, 8 Oct 2012 21:56:12 +1100 Subject: [PATCH 01/10] xfs: only update the last_sync_lsn when a transaction completes The log write code stamps each iclog with the current tail LSN in the iclog header so that recovery knows where to find the tail of thelog once it has found the head. Normally this is taken from the first item on the AIL - the log item that corresponds to the oldest active item in the log. The problem is that when the AIL is empty, the tail lsn is dervied from the the l_last_sync_lsn, which is the LSN of the last iclog to be written to the log. In most cases this doesn't happen, because the AIL is rarely empty on an active filesystem. However, when it does, it opens up an interesting case when the transaction being committed to the iclog spans multiple iclogs. That is, the first iclog is stamped with the l_last_sync_lsn, and IO is issued. Then the next iclog is setup, the changes copied into the iclog (takes some time), and then the l_last_sync_lsn is stamped into the header and IO is issued. This is still the same transaction, so the tail lsn of both iclogs must be the same for log recovery to find the entire transaction to be able to replay it. The problem arises in that the iclog buffer IO completion updates the l_last_sync_lsn with it's own LSN. Therefore, If the first iclog completes it's IO before the second iclog is filled and has the tail lsn stamped in it, it will stamp the LSN of the first iclog into it's tail lsn field. If the system fails at this point, log recovery will not see a complete transaction, so the transaction will no be replayed. The fix is simple - the l_last_sync_lsn is updated when a iclog buffer IO completes, and this is incorrect. The l_last_sync_lsn shoul dbe updated when a transaction is completed by a iclog buffer IO. That is, only iclog buffers that have transaction commit callbacks attached to them should update the l_last_sync_lsn. This means that the last_sync_lsn will only move forward when a commit record it written, not in the middle of a large transaction that is rolling through multiple iclog buffers. Signed-off-by: Dave Chinner Reviewed-by: Mark Tinguely Reviewed-by: Christoph Hellwig Signed-off-by: Ben Myers --- fs/xfs/xfs_log.c | 19 ++++++++++++++++--- 1 file changed, 16 insertions(+), 3 deletions(-) diff --git a/fs/xfs/xfs_log.c b/fs/xfs/xfs_log.c index 7f4f9370d0e7..4dad756962d0 100644 --- a/fs/xfs/xfs_log.c +++ b/fs/xfs/xfs_log.c @@ -2387,14 +2387,27 @@ xlog_state_do_callback( /* - * update the last_sync_lsn before we drop the + * Completion of a iclog IO does not imply that + * a transaction has completed, as transactions + * can be large enough to span many iclogs. We + * cannot change the tail of the log half way + * through a transaction as this may be the only + * transaction in the log and moving th etail to + * point to the middle of it will prevent + * recovery from finding the start of the + * transaction. Hence we should only update the + * last_sync_lsn if this iclog contains + * transaction completion callbacks on it. + * + * We have to do this before we drop the * icloglock to ensure we are the only one that * can update it. */ ASSERT(XFS_LSN_CMP(atomic64_read(&log->l_last_sync_lsn), be64_to_cpu(iclog->ic_header.h_lsn)) <= 0); - atomic64_set(&log->l_last_sync_lsn, - be64_to_cpu(iclog->ic_header.h_lsn)); + if (iclog->ic_callback) + atomic64_set(&log->l_last_sync_lsn, + be64_to_cpu(iclog->ic_header.h_lsn)); } else ioerrors++; From 408cc4e97a3ccd172d2d676e4b585badf439271b Mon Sep 17 00:00:00 2001 From: Mark Tinguely Date: Thu, 20 Sep 2012 13:16:45 -0500 Subject: [PATCH 02/10] xfs: zero allocation_args on the kernel stack Zero the kernel stack space that makes up the xfs_alloc_arg structures. Signed-off-by: Mark Tinguely Reviewed-by: Ben Myers Signed-off-by: Ben Myers --- fs/xfs/xfs_alloc.c | 1 + fs/xfs/xfs_bmap.c | 3 +++ fs/xfs/xfs_ialloc.c | 1 + 3 files changed, 5 insertions(+) diff --git a/fs/xfs/xfs_alloc.c b/fs/xfs/xfs_alloc.c index 4f33c32affe3..0287f3b1b503 100644 --- a/fs/xfs/xfs_alloc.c +++ b/fs/xfs/xfs_alloc.c @@ -1866,6 +1866,7 @@ xfs_alloc_fix_freelist( /* * Initialize the args structure. */ + memset(&targs, 0, sizeof(targs)); targs.tp = tp; targs.mp = mp; targs.agbp = agbp; diff --git a/fs/xfs/xfs_bmap.c b/fs/xfs/xfs_bmap.c index 848ffa77707b..e1545ec2f7d2 100644 --- a/fs/xfs/xfs_bmap.c +++ b/fs/xfs/xfs_bmap.c @@ -2437,6 +2437,7 @@ xfs_bmap_btalloc( * Normal allocation, done through xfs_alloc_vextent. */ tryagain = isaligned = 0; + memset(&args, 0, sizeof(args)); args.tp = ap->tp; args.mp = mp; args.fsbno = ap->blkno; @@ -3082,6 +3083,7 @@ xfs_bmap_extents_to_btree( * Convert to a btree with two levels, one record in root. */ XFS_IFORK_FMT_SET(ip, whichfork, XFS_DINODE_FMT_BTREE); + memset(&args, 0, sizeof(args)); args.tp = tp; args.mp = mp; args.firstblock = *firstblock; @@ -3237,6 +3239,7 @@ xfs_bmap_local_to_extents( xfs_buf_t *bp; /* buffer for extent block */ xfs_bmbt_rec_host_t *ep;/* extent record pointer */ + memset(&args, 0, sizeof(args)); args.tp = tp; args.mp = ip->i_mount; args.firstblock = *firstblock; diff --git a/fs/xfs/xfs_ialloc.c b/fs/xfs/xfs_ialloc.c index 445bf1aef31c..c5c4ef4f2bdb 100644 --- a/fs/xfs/xfs_ialloc.c +++ b/fs/xfs/xfs_ialloc.c @@ -250,6 +250,7 @@ xfs_ialloc_ag_alloc( /* boundary */ struct xfs_perag *pag; + memset(&args, 0, sizeof(args)); args.tp = tp; args.mp = tp->t_mountp; From 326c03555b914ff153ba5b40df87fd6e28e7e367 Mon Sep 17 00:00:00 2001 From: Dave Chinner Date: Fri, 5 Oct 2012 11:06:58 +1000 Subject: [PATCH 03/10] xfs: introduce XFS_BMAPI_STACK_SWITCH Certain allocation paths through xfs_bmapi_write() are in situations where we have limited stack available. These are almost always in the buffered IO writeback path when convertion delayed allocation extents to real extents. The current stack switch occurs for userdata allocations, which means we also do stack switches for preallocation, direct IO and unwritten extent conversion, even those these call chains have never been implicated in a stack overrun. Hence, let's target just the single stack overun offended for stack switches. To do that, introduce a XFS_BMAPI_STACK_SWITCH flag that the caller can pass xfs_bmapi_write() to indicate it should switch stacks if it needs to do allocation. Signed-off-by: Dave Chinner Reviewed-by: Mark Tinguely Signed-off-by: Ben Myers --- fs/xfs/xfs_alloc.c | 2 +- fs/xfs/xfs_alloc.h | 1 + fs/xfs/xfs_bmap.c | 4 ++++ fs/xfs/xfs_bmap.h | 5 ++++- fs/xfs/xfs_iomap.c | 4 +++- 5 files changed, 13 insertions(+), 3 deletions(-) diff --git a/fs/xfs/xfs_alloc.c b/fs/xfs/xfs_alloc.c index 0287f3b1b503..43f791bcd8b1 100644 --- a/fs/xfs/xfs_alloc.c +++ b/fs/xfs/xfs_alloc.c @@ -2447,7 +2447,7 @@ xfs_alloc_vextent( { DECLARE_COMPLETION_ONSTACK(done); - if (!args->userdata) + if (!args->stack_switch) return __xfs_alloc_vextent(args); diff --git a/fs/xfs/xfs_alloc.h b/fs/xfs/xfs_alloc.h index 93be4a667ca1..ef7d4885dc2d 100644 --- a/fs/xfs/xfs_alloc.h +++ b/fs/xfs/xfs_alloc.h @@ -123,6 +123,7 @@ typedef struct xfs_alloc_arg { struct completion *done; struct work_struct work; int result; + char stack_switch; } xfs_alloc_arg_t; /* diff --git a/fs/xfs/xfs_bmap.c b/fs/xfs/xfs_bmap.c index e1545ec2f7d2..91259554df8b 100644 --- a/fs/xfs/xfs_bmap.c +++ b/fs/xfs/xfs_bmap.c @@ -2441,6 +2441,7 @@ xfs_bmap_btalloc( args.tp = ap->tp; args.mp = mp; args.fsbno = ap->blkno; + args.stack_switch = ap->stack_switch; /* Trim the allocation back to the maximum an AG can fit. */ args.maxlen = MIN(ap->length, XFS_ALLOC_AG_MAX_USABLE(mp)); @@ -4675,6 +4676,9 @@ xfs_bmapi_allocate( return error; } + if (flags & XFS_BMAPI_STACK_SWITCH) + bma->stack_switch = 1; + error = xfs_bmap_alloc(bma); if (error) return error; diff --git a/fs/xfs/xfs_bmap.h b/fs/xfs/xfs_bmap.h index 803b56d7ce16..b68c598034c1 100644 --- a/fs/xfs/xfs_bmap.h +++ b/fs/xfs/xfs_bmap.h @@ -77,6 +77,7 @@ typedef struct xfs_bmap_free * from written to unwritten, otherwise convert from unwritten to written. */ #define XFS_BMAPI_CONVERT 0x040 +#define XFS_BMAPI_STACK_SWITCH 0x080 #define XFS_BMAPI_FLAGS \ { XFS_BMAPI_ENTIRE, "ENTIRE" }, \ @@ -85,7 +86,8 @@ typedef struct xfs_bmap_free { XFS_BMAPI_PREALLOC, "PREALLOC" }, \ { XFS_BMAPI_IGSTATE, "IGSTATE" }, \ { XFS_BMAPI_CONTIG, "CONTIG" }, \ - { XFS_BMAPI_CONVERT, "CONVERT" } + { XFS_BMAPI_CONVERT, "CONVERT" }, \ + { XFS_BMAPI_STACK_SWITCH, "STACK_SWITCH" } static inline int xfs_bmapi_aflag(int w) @@ -133,6 +135,7 @@ typedef struct xfs_bmalloca { char userdata;/* set if is user data */ char aeof; /* allocated space at eof */ char conv; /* overwriting unwritten extents */ + char stack_switch; } xfs_bmalloca_t; /* diff --git a/fs/xfs/xfs_iomap.c b/fs/xfs/xfs_iomap.c index 973dff6ad935..7f537663365b 100644 --- a/fs/xfs/xfs_iomap.c +++ b/fs/xfs/xfs_iomap.c @@ -584,7 +584,9 @@ xfs_iomap_write_allocate( * pointer that the caller gave to us. */ error = xfs_bmapi_write(tp, ip, map_start_fsb, - count_fsb, 0, &first_block, 1, + count_fsb, + XFS_BMAPI_STACK_SWITCH, + &first_block, 1, imap, &nimaps, &free_list); if (error) goto trans_cancel; From 1f3c785c3adb7d2b109ec7c8f10081d1294b03d3 Mon Sep 17 00:00:00 2001 From: Dave Chinner Date: Fri, 5 Oct 2012 11:06:59 +1000 Subject: [PATCH 04/10] xfs: move allocation stack switch up to xfs_bmapi_allocate Switching stacks are xfs_alloc_vextent can cause deadlocks when we run out of worker threads on the allocation workqueue. This can occur because xfs_bmap_btalloc can make multiple calls to xfs_alloc_vextent() and even if xfs_alloc_vextent() fails it can return with the AGF locked in the current allocation transaction. If we then need to make another allocation, and all the allocation worker contexts are exhausted because the are blocked waiting for the AGF lock, holder of the AGF cannot get it's xfs-alloc_vextent work completed to release the AGF. Hence allocation effectively deadlocks. To avoid this, move the stack switch one layer up to xfs_bmapi_allocate() so that all of the allocation attempts in a single switched stack transaction occur in a single worker context. This avoids the problem of an allocation being blocked waiting for a worker thread whilst holding the AGF. Signed-off-by: Dave Chinner Reviewed-by: Mark Tinguely Signed-off-by: Ben Myers --- fs/xfs/xfs_alloc.c | 42 +------------------------------- fs/xfs/xfs_alloc.h | 4 ---- fs/xfs/xfs_bmap.c | 60 +++++++++++++++++++++++++++++++++++++--------- fs/xfs/xfs_bmap.h | 4 ++++ 4 files changed, 54 insertions(+), 56 deletions(-) diff --git a/fs/xfs/xfs_alloc.c b/fs/xfs/xfs_alloc.c index 43f791bcd8b1..335206a9c698 100644 --- a/fs/xfs/xfs_alloc.c +++ b/fs/xfs/xfs_alloc.c @@ -2208,7 +2208,7 @@ xfs_alloc_read_agf( * group or loop over the allocation groups to find the result. */ int /* error */ -__xfs_alloc_vextent( +xfs_alloc_vextent( xfs_alloc_arg_t *args) /* allocation argument structure */ { xfs_agblock_t agsize; /* allocation group size */ @@ -2418,46 +2418,6 @@ error0: return error; } -static void -xfs_alloc_vextent_worker( - struct work_struct *work) -{ - struct xfs_alloc_arg *args = container_of(work, - struct xfs_alloc_arg, work); - unsigned long pflags; - - /* we are in a transaction context here */ - current_set_flags_nested(&pflags, PF_FSTRANS); - - args->result = __xfs_alloc_vextent(args); - complete(args->done); - - current_restore_flags_nested(&pflags, PF_FSTRANS); -} - -/* - * Data allocation requests often come in with little stack to work on. Push - * them off to a worker thread so there is lots of stack to use. Metadata - * requests, OTOH, are generally from low stack usage paths, so avoid the - * context switch overhead here. - */ -int -xfs_alloc_vextent( - struct xfs_alloc_arg *args) -{ - DECLARE_COMPLETION_ONSTACK(done); - - if (!args->stack_switch) - return __xfs_alloc_vextent(args); - - - args->done = &done; - INIT_WORK_ONSTACK(&args->work, xfs_alloc_vextent_worker); - queue_work(xfs_alloc_wq, &args->work); - wait_for_completion(&done); - return args->result; -} - /* * Free an extent. * Just break up the extent address and hand off to xfs_free_ag_extent diff --git a/fs/xfs/xfs_alloc.h b/fs/xfs/xfs_alloc.h index ef7d4885dc2d..feacb061bab7 100644 --- a/fs/xfs/xfs_alloc.h +++ b/fs/xfs/xfs_alloc.h @@ -120,10 +120,6 @@ typedef struct xfs_alloc_arg { char isfl; /* set if is freelist blocks - !acctg */ char userdata; /* set if this is user data */ xfs_fsblock_t firstblock; /* io first block allocated */ - struct completion *done; - struct work_struct work; - int result; - char stack_switch; } xfs_alloc_arg_t; /* diff --git a/fs/xfs/xfs_bmap.c b/fs/xfs/xfs_bmap.c index 91259554df8b..83d0cf3df930 100644 --- a/fs/xfs/xfs_bmap.c +++ b/fs/xfs/xfs_bmap.c @@ -2441,7 +2441,6 @@ xfs_bmap_btalloc( args.tp = ap->tp; args.mp = mp; args.fsbno = ap->blkno; - args.stack_switch = ap->stack_switch; /* Trim the allocation back to the maximum an AG can fit. */ args.maxlen = MIN(ap->length, XFS_ALLOC_AG_MAX_USABLE(mp)); @@ -4620,12 +4619,11 @@ xfs_bmapi_delay( STATIC int -xfs_bmapi_allocate( - struct xfs_bmalloca *bma, - int flags) +__xfs_bmapi_allocate( + struct xfs_bmalloca *bma) { struct xfs_mount *mp = bma->ip->i_mount; - int whichfork = (flags & XFS_BMAPI_ATTRFORK) ? + int whichfork = (bma->flags & XFS_BMAPI_ATTRFORK) ? XFS_ATTR_FORK : XFS_DATA_FORK; struct xfs_ifork *ifp = XFS_IFORK_PTR(bma->ip, whichfork); int tmp_logflags = 0; @@ -4658,25 +4656,25 @@ xfs_bmapi_allocate( * Indicate if this is the first user data in the file, or just any * user data. */ - if (!(flags & XFS_BMAPI_METADATA)) { + if (!(bma->flags & XFS_BMAPI_METADATA)) { bma->userdata = (bma->offset == 0) ? XFS_ALLOC_INITIAL_USER_DATA : XFS_ALLOC_USERDATA; } - bma->minlen = (flags & XFS_BMAPI_CONTIG) ? bma->length : 1; + bma->minlen = (bma->flags & XFS_BMAPI_CONTIG) ? bma->length : 1; /* * Only want to do the alignment at the eof if it is userdata and * allocation length is larger than a stripe unit. */ if (mp->m_dalign && bma->length >= mp->m_dalign && - !(flags & XFS_BMAPI_METADATA) && whichfork == XFS_DATA_FORK) { + !(bma->flags & XFS_BMAPI_METADATA) && whichfork == XFS_DATA_FORK) { error = xfs_bmap_isaeof(bma, whichfork); if (error) return error; } - if (flags & XFS_BMAPI_STACK_SWITCH) + if (bma->flags & XFS_BMAPI_STACK_SWITCH) bma->stack_switch = 1; error = xfs_bmap_alloc(bma); @@ -4713,7 +4711,7 @@ xfs_bmapi_allocate( * A wasdelay extent has been initialized, so shouldn't be flagged * as unwritten. */ - if (!bma->wasdel && (flags & XFS_BMAPI_PREALLOC) && + if (!bma->wasdel && (bma->flags & XFS_BMAPI_PREALLOC) && xfs_sb_version_hasextflgbit(&mp->m_sb)) bma->got.br_state = XFS_EXT_UNWRITTEN; @@ -4741,6 +4739,45 @@ xfs_bmapi_allocate( return 0; } +static void +xfs_bmapi_allocate_worker( + struct work_struct *work) +{ + struct xfs_bmalloca *args = container_of(work, + struct xfs_bmalloca, work); + unsigned long pflags; + + /* we are in a transaction context here */ + current_set_flags_nested(&pflags, PF_FSTRANS); + + args->result = __xfs_bmapi_allocate(args); + complete(args->done); + + current_restore_flags_nested(&pflags, PF_FSTRANS); +} + +/* + * Some allocation requests often come in with little stack to work on. Push + * them off to a worker thread so there is lots of stack to use. Otherwise just + * call directly to avoid the context switch overhead here. + */ +int +xfs_bmapi_allocate( + struct xfs_bmalloca *args) +{ + DECLARE_COMPLETION_ONSTACK(done); + + if (!args->stack_switch) + return __xfs_bmapi_allocate(args); + + + args->done = &done; + INIT_WORK_ONSTACK(&args->work, xfs_bmapi_allocate_worker); + queue_work(xfs_alloc_wq, &args->work); + wait_for_completion(&done); + return args->result; +} + STATIC int xfs_bmapi_convert_unwritten( struct xfs_bmalloca *bma, @@ -4926,6 +4963,7 @@ xfs_bmapi_write( bma.conv = !!(flags & XFS_BMAPI_CONVERT); bma.wasdel = wasdelay; bma.offset = bno; + bma.flags = flags; /* * There's a 32/64 bit type mismatch between the @@ -4941,7 +4979,7 @@ xfs_bmapi_write( ASSERT(len > 0); ASSERT(bma.length > 0); - error = xfs_bmapi_allocate(&bma, flags); + error = xfs_bmapi_allocate(&bma); if (error) goto error0; if (bma.blkno == NULLFSBLOCK) diff --git a/fs/xfs/xfs_bmap.h b/fs/xfs/xfs_bmap.h index b68c598034c1..5f469c3516eb 100644 --- a/fs/xfs/xfs_bmap.h +++ b/fs/xfs/xfs_bmap.h @@ -136,6 +136,10 @@ typedef struct xfs_bmalloca { char aeof; /* allocated space at eof */ char conv; /* overwriting unwritten extents */ char stack_switch; + int flags; + struct completion *done; + struct work_struct work; + int result; } xfs_bmalloca_t; /* From eaef854335ce09956e930fe4a193327417edc6c9 Mon Sep 17 00:00:00 2001 From: Dave Chinner Date: Tue, 9 Oct 2012 14:50:52 +1100 Subject: [PATCH 05/10] xfs: growfs: don't read garbage for new secondary superblocks When updating new secondary superblocks in a growfs operation, the superblock buffer is read from the newly grown region of the underlying device. This is not guaranteed to be zero, so violates the underlying assumption that the unused parts of superblocks are zero filled. Get a new buffer for these secondary superblocks to ensure that the unused regions are zero filled correctly. Signed-off-by: Dave Chinner Reviewed-by: Carlos Maiolino Signed-off-by: Ben Myers --- fs/xfs/xfs_fsops.c | 21 +++++++++++++++++++-- 1 file changed, 19 insertions(+), 2 deletions(-) diff --git a/fs/xfs/xfs_fsops.c b/fs/xfs/xfs_fsops.c index c25b094efbf7..4beaede43277 100644 --- a/fs/xfs/xfs_fsops.c +++ b/fs/xfs/xfs_fsops.c @@ -399,9 +399,26 @@ xfs_growfs_data_private( /* update secondary superblocks. */ for (agno = 1; agno < nagcount; agno++) { - error = xfs_trans_read_buf(mp, NULL, mp->m_ddev_targp, + error = 0; + /* + * new secondary superblocks need to be zeroed, not read from + * disk as the contents of the new area we are growing into is + * completely unknown. + */ + if (agno < oagcount) { + error = xfs_trans_read_buf(mp, NULL, mp->m_ddev_targp, XFS_AGB_TO_DADDR(mp, agno, XFS_SB_BLOCK(mp)), XFS_FSS_TO_BB(mp, 1), 0, &bp); + } else { + bp = xfs_trans_get_buf(NULL, mp->m_ddev_targp, + XFS_AGB_TO_DADDR(mp, agno, XFS_SB_BLOCK(mp)), + XFS_FSS_TO_BB(mp, 1), 0); + if (bp) + xfs_buf_zero(bp, 0, BBTOB(bp->b_length)); + else + error = ENOMEM; + } + if (error) { xfs_warn(mp, "error %d reading secondary superblock for ag %d", @@ -423,7 +440,7 @@ xfs_growfs_data_private( break; /* no point in continuing */ } } - return 0; + return error; error0: xfs_trans_cancel(tp, XFS_TRANS_ABORT); From 1e7acbb7bc1ae7c1c62fd1310b3176a820225056 Mon Sep 17 00:00:00 2001 From: Dave Chinner Date: Thu, 25 Oct 2012 17:22:30 +1100 Subject: [PATCH 06/10] xfs: silence uninitialised f.file warning. Uninitialised variable build warning introduced by 2903ff0 ("switch simple cases of fget_light to fdget"), gcc is not smart enough to work out that the variable is not used uninitialised, and the commit removed the initialisation at declaration that the old variable had. Signed-off-by: Dave Chinner Reviewed-by: Christoph Hellwig Reviewed-by: Mark Tinguely Signed-off-by: Ben Myers --- fs/xfs/xfs_ioctl.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/fs/xfs/xfs_ioctl.c b/fs/xfs/xfs_ioctl.c index 8305f2ac6773..c1df3c623de2 100644 --- a/fs/xfs/xfs_ioctl.c +++ b/fs/xfs/xfs_ioctl.c @@ -70,7 +70,7 @@ xfs_find_handle( int hsize; xfs_handle_t handle; struct inode *inode; - struct fd f; + struct fd f = {0}; struct path path; int error; struct xfs_inode *ip; From ca250b1b3d711936d7dae9e97871f2261347f82d Mon Sep 17 00:00:00 2001 From: Dave Chinner Date: Fri, 2 Nov 2012 11:38:41 +1100 Subject: [PATCH 07/10] xfs: invalidate allocbt blocks moved to the free list When we free a block from the alloc btree tree, we move it to the freelist held in the AGFL and mark it busy in the busy extent tree. This typically happens when we merge btree blocks. Once the transaction is committed and checkpointed, the block can remain on the free list for an indefinite amount of time. Now, this isn't the end of the world at this point - if the free list is shortened, the buffer is invalidated in the transaction that moves it back to free space. If the buffer is allocated as metadata from the free list, then all the modifications getted logged, and we have no issues, either. And if it gets allocated as userdata direct from the freelist, it gets invalidated and so will never get written. However, during the time it sits on the free list, pressure on the log can cause the AIL to be pushed and the buffer that covers the block gets pushed for write. IOWs, we end up writing a freed metadata block to disk. Again, this isn't the end of the world because we know from the above we are only writing to free space. The problem, however, is for validation callbacks. If the block was on old btree root block, then the level of the block is going to be higher than the current tree root, and so will fail validation. There may be other inconsistencies in the block as well, and currently we don't care because the block is in free space. Shutting down the filesystem because a freed block doesn't pass write validation, OTOH, is rather unfriendly. So, make sure we always invalidate buffers as they move from the free space trees to the free list so that we guarantee they never get written to disk while on the free list. Signed-off-by: Dave Chinner Reviewed-by: Christoph Hellwig Reviewed-by: Phil White Reviewed-by: Mark Tinguely Signed-off-by: Ben Myers --- fs/xfs/xfs_alloc_btree.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/fs/xfs/xfs_alloc_btree.c b/fs/xfs/xfs_alloc_btree.c index f1647caace8f..f7876c6d6165 100644 --- a/fs/xfs/xfs_alloc_btree.c +++ b/fs/xfs/xfs_alloc_btree.c @@ -121,6 +121,8 @@ xfs_allocbt_free_block( xfs_extent_busy_insert(cur->bc_tp, be32_to_cpu(agf->agf_seqno), bno, 1, XFS_EXTENT_BUSY_SKIP_DISCARD); xfs_trans_agbtree_delta(cur->bc_tp, -1); + + xfs_trans_binval(cur->bc_tp, bp); return 0; } From 4b62acfe99e158fb7812982d1cf90a075710a92c Mon Sep 17 00:00:00 2001 From: Dave Chinner Date: Fri, 2 Nov 2012 11:38:42 +1100 Subject: [PATCH 08/10] xfs: don't vmap inode cluster buffers during free Inode buffers do not need to be mapped as inodes are read or written directly from/to the pages underlying the buffer. This fixes a regression introduced by commit 611c994 ("xfs: make XBF_MAPPED the default behaviour"). Signed-off-by: Dave Chinner Reviewed-by: Christoph Hellwig Reviewed-by: Mark Tinguely Signed-off-by: Ben Myers --- fs/xfs/xfs_inode.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/fs/xfs/xfs_inode.c b/fs/xfs/xfs_inode.c index 2778258fcfa2..1938b41ee9f5 100644 --- a/fs/xfs/xfs_inode.c +++ b/fs/xfs/xfs_inode.c @@ -1509,7 +1509,8 @@ xfs_ifree_cluster( * to mark all the active inodes on the buffer stale. */ bp = xfs_trans_get_buf(tp, mp->m_ddev_targp, blkno, - mp->m_bsize * blks_per_cluster, 0); + mp->m_bsize * blks_per_cluster, + XBF_UNMAPPED); if (!bp) return ENOMEM; From 03b1293edad462ad1ad62bcc5160c76758e450d5 Mon Sep 17 00:00:00 2001 From: Dave Chinner Date: Fri, 2 Nov 2012 14:23:12 +1100 Subject: [PATCH 09/10] xfs: fix buffer shudown reference count mismatch When we shut down the filesystem, we have to unpin and free all the buffers currently active in the CIL. To do this we unpin and remove them in one operation as a result of a failed iclogbuf write. For buffers, we do this removal via a simultated IO completion of after marking the buffer stale. At the time we do this, we have two references to the buffer - the active LRU reference and the buf log item. The LRU reference is removed by marking the buffer stale, and the active CIL reference is by the xfs_buf_iodone() callback that is run by xfs_buf_do_callbacks() during ioend processing (via the bp->b_iodone callback). However, ioend processing requires one more reference - that of the IO that it is completing. We don't have this reference, so we free the buffer prematurely and use it after it is freed. For buffers marked with XBF_ASYNC, this leads to assert failures in xfs_buf_rele() on debug kernels because the b_hold count is zero. Fix this by making sure we take the necessary IO reference before starting IO completion processing on the stale buffer, and set the XBF_ASYNC flag to ensure that IO completion processing removes all the active references from the buffer to ensure it is fully torn down. Cc: Signed-off-by: Dave Chinner Reviewed-by: Mark Tinguely Signed-off-by: Ben Myers --- fs/xfs/xfs_buf_item.c | 18 ++++++++++++++++++ 1 file changed, 18 insertions(+) diff --git a/fs/xfs/xfs_buf_item.c b/fs/xfs/xfs_buf_item.c index a8d0ed911196..becf4a97efc6 100644 --- a/fs/xfs/xfs_buf_item.c +++ b/fs/xfs/xfs_buf_item.c @@ -526,7 +526,25 @@ xfs_buf_item_unpin( } xfs_buf_relse(bp); } else if (freed && remove) { + /* + * There are currently two references to the buffer - the active + * LRU reference and the buf log item. What we are about to do + * here - simulate a failed IO completion - requires 3 + * references. + * + * The LRU reference is removed by the xfs_buf_stale() call. The + * buf item reference is removed by the xfs_buf_iodone() + * callback that is run by xfs_buf_do_callbacks() during ioend + * processing (via the bp->b_iodone callback), and then finally + * the ioend processing will drop the IO reference if the buffer + * is marked XBF_ASYNC. + * + * Hence we need to take an additional reference here so that IO + * completion processing doesn't free the buffer prematurely. + */ xfs_buf_lock(bp); + xfs_buf_hold(bp); + bp->b_flags |= XBF_ASYNC; xfs_buf_ioerror(bp, EIO); XFS_BUF_UNDONE(bp); xfs_buf_stale(bp); From 6ce377afd1755eae5c93410ca9a1121dfead7b87 Mon Sep 17 00:00:00 2001 From: Dave Chinner Date: Fri, 2 Nov 2012 11:38:44 +1100 Subject: [PATCH 10/10] xfs: fix reading of wrapped log data Commit 4439647 ("xfs: reset buffer pointers before freeing them") in 3.0-rc1 introduced a regression when recovering log buffers that wrapped around the end of log. The second part of the log buffer at the start of the physical log was being read into the header buffer rather than the data buffer, and hence recovery was seeing garbage in the data buffer when it got to the region of the log buffer that was incorrectly read. Cc: # 3.0.x, 3.2.x, 3.4.x 3.6.x Reported-by: Torsten Kaiser Signed-off-by: Dave Chinner Reviewed-by: Christoph Hellwig Reviewed-by: Mark Tinguely Signed-off-by: Ben Myers --- fs/xfs/xfs_log_recover.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/fs/xfs/xfs_log_recover.c b/fs/xfs/xfs_log_recover.c index 5da3ace352bf..d308749fabf1 100644 --- a/fs/xfs/xfs_log_recover.c +++ b/fs/xfs/xfs_log_recover.c @@ -3541,7 +3541,7 @@ xlog_do_recovery_pass( * - order is important. */ error = xlog_bread_offset(log, 0, - bblks - split_bblks, hbp, + bblks - split_bblks, dbp, offset + BBTOB(split_bblks)); if (error) goto bread_err2;