From fa5a4f57ddbece604e07abfe98e01f520635411d Mon Sep 17 00:00:00 2001 From: Brian Foster Date: Tue, 21 Jun 2016 11:53:28 +1000 Subject: xfs: cancel eofblocks background trimming on remount read-only The filesystem quiesce sequence performs the operations necessary to drain all background work, push pending transactions through the log infrastructure and wait on I/O resulting from the final AIL push. We have had reports of remount,ro hangs in xfs_log_quiesce() -> xfs_wait_buftarg(), however, and some instrumentation code to detect transaction commits at this point in the quiesce sequence has inculpated the eofblocks background scanner as a cause. While higher level remount code generally prevents user modifications by the time the filesystem has made it to xfs_log_quiesce(), the background scanner may still be alive and can perform pending work at any time. If this occurs between the xfs_log_force() and xfs_wait_buftarg() calls within xfs_log_quiesce(), this can lead to an indefinite lockup in xfs_wait_buftarg(). To prevent this problem, cancel the background eofblocks scan worker during the remount read-only quiesce sequence. This suspends background trimming when a filesystem is remounted read-only. This is only done in the remount path because the freeze codepath has already locked out new transactions by the time the filesystem attempts to quiesce (and thus waiting on an active work item could deadlock). Kick the eofblocks worker to pick up where it left off once an fs is remounted back to read-write. Signed-off-by: Brian Foster Reviewed-by: Eric Sandeen Signed-off-by: Dave Chinner --- fs/xfs/xfs_super.c | 8 ++++++++ 1 file changed, 8 insertions(+) (limited to 'fs/xfs/xfs_super.c') diff --git a/fs/xfs/xfs_super.c b/fs/xfs/xfs_super.c index 11ea5d51db56..2d2810851871 100644 --- a/fs/xfs/xfs_super.c +++ b/fs/xfs/xfs_super.c @@ -1294,6 +1294,7 @@ xfs_fs_remount( */ xfs_restore_resvblks(mp); xfs_log_work_queue(mp); + xfs_queue_eofblocks(mp); } /* rw -> ro */ @@ -1306,6 +1307,13 @@ xfs_fs_remount( * return it to the same size. */ xfs_save_resvblks(mp); + + /* + * Cancel background eofb scanning so it cannot race with the + * final log force+buftarg wait and deadlock the remount. + */ + cancel_delayed_work_sync(&mp->m_eofblocks_work); + xfs_quiesce_attr(mp); mp->m_flags |= XFS_MOUNT_RDONLY; } -- cgit v1.2.3 From e66a4c678e64932eb4befd95a348b9632603d27c Mon Sep 17 00:00:00 2001 From: "Darrick J. Wong" Date: Tue, 21 Jun 2016 11:53:28 +1000 Subject: xfs: convert list of extents to free into a regular list In struct xfs_bmap_free, convert the open-coded free extent list to a regular list, then use list_sort to sort it prior to processing. Signed-off-by: Darrick J. Wong Reviewed-by: Dave Chinner Signed-off-by: Dave Chinner --- fs/xfs/libxfs/xfs_bmap.c | 39 +++++++++++---------------------------- fs/xfs/libxfs/xfs_bmap.h | 14 ++++++++------ fs/xfs/xfs_bmap_util.c | 32 +++++++++++++++++++++++++------- fs/xfs/xfs_bmap_util.h | 1 - fs/xfs/xfs_super.c | 5 +++-- 5 files changed, 47 insertions(+), 44 deletions(-) (limited to 'fs/xfs/xfs_super.c') diff --git a/fs/xfs/libxfs/xfs_bmap.c b/fs/xfs/libxfs/xfs_bmap.c index 8847496f7ccb..2f2c85cc8117 100644 --- a/fs/xfs/libxfs/xfs_bmap.c +++ b/fs/xfs/libxfs/xfs_bmap.c @@ -575,9 +575,7 @@ xfs_bmap_add_free( xfs_fsblock_t bno, /* fs block number of extent */ xfs_filblks_t len) /* length of extent */ { - xfs_bmap_free_item_t *cur; /* current (next) element */ - xfs_bmap_free_item_t *new; /* new element */ - xfs_bmap_free_item_t *prev; /* previous element */ + struct xfs_bmap_free_item *new; /* new element */ #ifdef DEBUG xfs_agnumber_t agno; xfs_agblock_t agbno; @@ -597,17 +595,7 @@ xfs_bmap_add_free( new = kmem_zone_alloc(xfs_bmap_free_item_zone, KM_SLEEP); new->xbfi_startblock = bno; new->xbfi_blockcount = (xfs_extlen_t)len; - for (prev = NULL, cur = flist->xbf_first; - cur != NULL; - prev = cur, cur = cur->xbfi_next) { - if (cur->xbfi_startblock >= bno) - break; - } - if (prev) - prev->xbfi_next = new; - else - flist->xbf_first = new; - new->xbfi_next = cur; + list_add(&new->xbfi_list, &flist->xbf_flist); flist->xbf_count++; } @@ -617,14 +605,10 @@ xfs_bmap_add_free( */ void xfs_bmap_del_free( - xfs_bmap_free_t *flist, /* free item list header */ - xfs_bmap_free_item_t *prev, /* previous item on list, if any */ - xfs_bmap_free_item_t *free) /* list item to be freed */ + struct xfs_bmap_free *flist, /* free item list header */ + struct xfs_bmap_free_item *free) /* list item to be freed */ { - if (prev) - prev->xbfi_next = free->xbfi_next; - else - flist->xbf_first = free->xbfi_next; + list_del(&free->xbfi_list); flist->xbf_count--; kmem_zone_free(xfs_bmap_free_item_zone, free); } @@ -634,17 +618,16 @@ xfs_bmap_del_free( */ void xfs_bmap_cancel( - xfs_bmap_free_t *flist) /* list of bmap_free_items */ + struct xfs_bmap_free *flist) /* list of bmap_free_items */ { - xfs_bmap_free_item_t *free; /* free list item */ - xfs_bmap_free_item_t *next; + struct xfs_bmap_free_item *free; /* free list item */ if (flist->xbf_count == 0) return; - ASSERT(flist->xbf_first != NULL); - for (free = flist->xbf_first; free; free = next) { - next = free->xbfi_next; - xfs_bmap_del_free(flist, NULL, free); + while (!list_empty(&flist->xbf_flist)) { + free = list_first_entry(&flist->xbf_flist, + struct xfs_bmap_free_item, xbfi_list); + xfs_bmap_del_free(flist, free); } ASSERT(flist->xbf_count == 0); } diff --git a/fs/xfs/libxfs/xfs_bmap.h b/fs/xfs/libxfs/xfs_bmap.h index e081c7694fae..f1f3ae6c0a3f 100644 --- a/fs/xfs/libxfs/xfs_bmap.h +++ b/fs/xfs/libxfs/xfs_bmap.h @@ -62,12 +62,12 @@ struct xfs_bmalloca { * List of extents to be free "later". * The list is kept sorted on xbf_startblock. */ -typedef struct xfs_bmap_free_item +struct xfs_bmap_free_item { xfs_fsblock_t xbfi_startblock;/* starting fs block number */ xfs_extlen_t xbfi_blockcount;/* number of blocks in extent */ - struct xfs_bmap_free_item *xbfi_next; /* link to next entry */ -} xfs_bmap_free_item_t; + struct list_head xbfi_list; +}; /* * Header for free extent list. @@ -85,7 +85,7 @@ typedef struct xfs_bmap_free_item */ typedef struct xfs_bmap_free { - xfs_bmap_free_item_t *xbf_first; /* list of to-be-free extents */ + struct list_head xbf_flist; /* list of to-be-free extents */ int xbf_count; /* count of items on list */ int xbf_low; /* alloc in low mode */ } xfs_bmap_free_t; @@ -141,8 +141,10 @@ static inline int xfs_bmapi_aflag(int w) static inline void xfs_bmap_init(xfs_bmap_free_t *flp, xfs_fsblock_t *fbp) { - ((flp)->xbf_first = NULL, (flp)->xbf_count = 0, \ - (flp)->xbf_low = 0, *(fbp) = NULLFSBLOCK); + INIT_LIST_HEAD(&flp->xbf_flist); + flp->xbf_count = 0; + flp->xbf_low = 0; + *fbp = NULLFSBLOCK; } /* diff --git a/fs/xfs/xfs_bmap_util.c b/fs/xfs/xfs_bmap_util.c index 586bb64e674b..c53e07a87cd7 100644 --- a/fs/xfs/xfs_bmap_util.c +++ b/fs/xfs/xfs_bmap_util.c @@ -79,6 +79,23 @@ xfs_zero_extent( GFP_NOFS, true); } +/* Sort bmap items by AG. */ +static int +xfs_bmap_free_list_cmp( + void *priv, + struct list_head *a, + struct list_head *b) +{ + struct xfs_mount *mp = priv; + struct xfs_bmap_free_item *ra; + struct xfs_bmap_free_item *rb; + + ra = container_of(a, struct xfs_bmap_free_item, xbfi_list); + rb = container_of(b, struct xfs_bmap_free_item, xbfi_list); + return XFS_FSB_TO_AGNO(mp, ra->xbfi_startblock) - + XFS_FSB_TO_AGNO(mp, rb->xbfi_startblock); +} + /* * Routine to be called at transaction's end by xfs_bmapi, xfs_bunmapi * caller. Frees all the extents that need freeing, which must be done @@ -99,14 +116,15 @@ xfs_bmap_finish( int error; /* error return value */ int committed;/* xact committed or not */ struct xfs_bmap_free_item *free; /* free extent item */ - struct xfs_bmap_free_item *next; /* next item on free list */ ASSERT((*tp)->t_flags & XFS_TRANS_PERM_LOG_RES); if (flist->xbf_count == 0) return 0; + list_sort((*tp)->t_mountp, &flist->xbf_flist, xfs_bmap_free_list_cmp); + efi = xfs_trans_get_efi(*tp, flist->xbf_count); - for (free = flist->xbf_first; free; free = free->xbfi_next) + list_for_each_entry(free, &flist->xbf_flist, xbfi_list) xfs_trans_log_efi_extent(*tp, efi, free->xbfi_startblock, free->xbfi_blockcount); @@ -138,15 +156,15 @@ xfs_bmap_finish( * on error. */ efd = xfs_trans_get_efd(*tp, efi, flist->xbf_count); - for (free = flist->xbf_first; free != NULL; free = next) { - next = free->xbfi_next; - + while (!list_empty(&flist->xbf_flist)) { + free = list_first_entry(&flist->xbf_flist, + struct xfs_bmap_free_item, xbfi_list); error = xfs_trans_free_extent(*tp, efd, free->xbfi_startblock, free->xbfi_blockcount); if (error) return error; - xfs_bmap_del_free(flist, NULL, free); + xfs_bmap_del_free(flist, free); } return 0; @@ -799,7 +817,7 @@ xfs_bmap_punch_delalloc_range( if (error) break; - ASSERT(!flist.xbf_count && !flist.xbf_first); + ASSERT(!flist.xbf_count && list_empty(&flist.xbf_flist)); next_block: start_fsb++; remaining--; diff --git a/fs/xfs/xfs_bmap_util.h b/fs/xfs/xfs_bmap_util.h index af97d9a1dfb4..4ec85d1043a0 100644 --- a/fs/xfs/xfs_bmap_util.h +++ b/fs/xfs/xfs_bmap_util.h @@ -43,7 +43,6 @@ int xfs_getbmap(struct xfs_inode *ip, struct getbmapx *bmv, /* functions in xfs_bmap.c that are only needed by xfs_bmap_util.c */ void xfs_bmap_del_free(struct xfs_bmap_free *flist, - struct xfs_bmap_free_item *prev, struct xfs_bmap_free_item *free); int xfs_bmap_extsize_align(struct xfs_mount *mp, struct xfs_bmbt_irec *gotp, struct xfs_bmbt_irec *prevp, xfs_extlen_t extsz, diff --git a/fs/xfs/xfs_super.c b/fs/xfs/xfs_super.c index 2d2810851871..5f3c7299532b 100644 --- a/fs/xfs/xfs_super.c +++ b/fs/xfs/xfs_super.c @@ -1700,8 +1700,9 @@ xfs_init_zones(void) if (!xfs_log_ticket_zone) goto out_free_ioend_bioset; - xfs_bmap_free_item_zone = kmem_zone_init(sizeof(xfs_bmap_free_item_t), - "xfs_bmap_free_item"); + xfs_bmap_free_item_zone = kmem_zone_init( + sizeof(struct xfs_bmap_free_item), + "xfs_bmap_free_item"); if (!xfs_bmap_free_item_zone) goto out_destroy_log_ticket_zone; -- cgit v1.2.3