5 files changed, 144 insertions, 20 deletions

diff --git a/fs/xfs/libxfs/xfs_ag_resv.c b/fs/xfs/libxfs/xfs_ag_resv.c
index 94234bff40dc..33db69be4832 100644
--- a/fs/xfs/libxfs/xfs_ag_resv.c
+++ b/fs/xfs/libxfs/xfs_ag_resv.c
@@ -39,6 +39,7 @@
 #include "xfs_rmap_btree.h"
 #include "xfs_btree.h"
 #include "xfs_refcount_btree.h"
+#include "xfs_ialloc_btree.h"
 
 /*
  * Per-AG Block Reservations
@@ -210,6 +211,9 @@ __xfs_ag_resv_init(
         if (error) {
                 trace_xfs_ag_resv_init_error(pag->pag_mount, pag->pag_agno,
                                 error, _RET_IP_);
+                xfs_warn(mp,
+"Per-AG reservation for AG %u failed.  Filesystem may run out of space.",
+                                pag->pag_agno);
                 return error;
         }
 
@@ -228,6 +232,8 @@ int
 xfs_ag_resv_init(
         struct xfs_perag                *pag)
 {
+        struct xfs_mount                *mp = pag->pag_mount;
+        xfs_agnumber_t                  agno = pag->pag_agno;
         xfs_extlen_t                    ask;
         xfs_extlen_t                    used;
         int                             error = 0;
@@ -236,23 +242,45 @@ xfs_ag_resv_init(
         if (pag->pag_meta_resv.ar_asked == 0) {
                 ask = used = 0;
 
-                error = xfs_refcountbt_calc_reserves(pag->pag_mount,
-                                pag->pag_agno, &ask, &used);
+                error = xfs_refcountbt_calc_reserves(mp, agno, &ask, &used);
                 if (error)
                         goto out;
 
-                error = __xfs_ag_resv_init(pag, XFS_AG_RESV_METADATA,
-                                ask, used);
+                error = xfs_finobt_calc_reserves(mp, agno, &ask, &used);
                 if (error)
                         goto out;
+
+                error = __xfs_ag_resv_init(pag, XFS_AG_RESV_METADATA,
+                                ask, used);
+                if (error) {
+                        /*
+                         * Because we didn't have per-AG reservations when the
+                         * finobt feature was added we might not be able to
+                         * reserve all needed blocks.  Warn and fall back to the
+                         * old and potentially buggy code in that case, but
+                         * ensure we do have the reservation for the refcountbt.
+                         */
+                        ask = used = 0;
+
+                        mp->m_inotbt_nores = true;
+
+                        error = xfs_refcountbt_calc_reserves(mp, agno, &ask,
+                                        &used);
+                        if (error)
+                                goto out;
+
+                        error = __xfs_ag_resv_init(pag, XFS_AG_RESV_METADATA,
+                                        ask, used);
+                        if (error)
+                                goto out;
+                }
         }
 
         /* Create the AGFL metadata reservation */
         if (pag->pag_agfl_resv.ar_asked == 0) {
                 ask = used = 0;
 
-                error = xfs_rmapbt_calc_reserves(pag->pag_mount, pag->pag_agno,
-                                &ask, &used);
+                error = xfs_rmapbt_calc_reserves(mp, agno, &ask, &used);
                 if (error)
                         goto out;
 
@@ -261,9 +289,16 @@ xfs_ag_resv_init(
                         goto out;
         }
 
+#ifdef DEBUG
+        /* need to read in the AGF for the ASSERT below to work */
+        error = xfs_alloc_pagf_init(pag->pag_mount, NULL, pag->pag_agno, 0);
+        if (error)
+                return error;
+
         ASSERT(xfs_perag_resv(pag, XFS_AG_RESV_METADATA)->ar_reserved +
                xfs_perag_resv(pag, XFS_AG_RESV_AGFL)->ar_reserved <=
                pag->pagf_freeblks + pag->pagf_flcount);
+#endif
 out:
         return error;
 }
diff --git a/fs/xfs/libxfs/xfs_ialloc_btree.c b/fs/xfs/libxfs/xfs_ialloc_btree.c
index 0fd086d03d41..7c471881c9a6 100644
--- a/fs/xfs/libxfs/xfs_ialloc_btree.c
+++ b/fs/xfs/libxfs/xfs_ialloc_btree.c
@@ -82,11 +82,12 @@ xfs_finobt_set_root(
 }
 
 STATIC int
-xfs_inobt_alloc_block(
+__xfs_inobt_alloc_block(
         struct xfs_btree_cur    *cur,
         union xfs_btree_ptr     *start,
         union xfs_btree_ptr     *new,
-        int                     *stat)
+        int                     *stat,
+        enum xfs_ag_resv_type   resv)
 {
         xfs_alloc_arg_t         args;           /* block allocation args */
         int                     error;          /* error return value */
@@ -103,6 +104,7 @@ xfs_inobt_alloc_block(
         args.maxlen = 1;
         args.prod = 1;
         args.type = XFS_ALLOCTYPE_NEAR_BNO;
+        args.resv = resv;
 
         error = xfs_alloc_vextent(&args);
         if (error) {
@@ -123,6 +125,27 @@ xfs_inobt_alloc_block(
 }
 
 STATIC int
+xfs_inobt_alloc_block(
+        struct xfs_btree_cur    *cur,
+        union xfs_btree_ptr     *start,
+        union xfs_btree_ptr     *new,
+        int                     *stat)
+{
+        return __xfs_inobt_alloc_block(cur, start, new, stat, XFS_AG_RESV_NONE);
+}
+
+STATIC int
+xfs_finobt_alloc_block(
+        struct xfs_btree_cur    *cur,
+        union xfs_btree_ptr     *start,
+        union xfs_btree_ptr     *new,
+        int                     *stat)
+{
+        return __xfs_inobt_alloc_block(cur, start, new, stat,
+                        XFS_AG_RESV_METADATA);
+}
+
+STATIC int
 xfs_inobt_free_block(
         struct xfs_btree_cur    *cur,
         struct xfs_buf          *bp)
@@ -328,7 +351,7 @@ static const struct xfs_btree_ops xfs_finobt_ops = {
 
         .dup_cursor             = xfs_inobt_dup_cursor,
         .set_root               = xfs_finobt_set_root,
-        .alloc_block            = xfs_inobt_alloc_block,
+        .alloc_block            = xfs_finobt_alloc_block,
         .free_block             = xfs_inobt_free_block,
         .get_minrecs            = xfs_inobt_get_minrecs,
         .get_maxrecs            = xfs_inobt_get_maxrecs,
@@ -480,3 +503,64 @@ xfs_inobt_rec_check_count(
         return 0;
 }
 #endif  /* DEBUG */
+
+static xfs_extlen_t
+xfs_inobt_max_size(
+        struct xfs_mount        *mp)
+{
+        /* Bail out if we're uninitialized, which can happen in mkfs. */
+        if (mp->m_inobt_mxr[0] == 0)
+                return 0;
+
+        return xfs_btree_calc_size(mp, mp->m_inobt_mnr,
+                (uint64_t)mp->m_sb.sb_agblocks * mp->m_sb.sb_inopblock /
+                                XFS_INODES_PER_CHUNK);
+}
+
+static int
+xfs_inobt_count_blocks(
+        struct xfs_mount        *mp,
+        xfs_agnumber_t          agno,
+        xfs_btnum_t             btnum,
+        xfs_extlen_t            *tree_blocks)
+{
+        struct xfs_buf          *agbp;
+        struct xfs_btree_cur    *cur;
+        int                     error;
+
+        error = xfs_ialloc_read_agi(mp, NULL, agno, &agbp);
+        if (error)
+                return error;
+
+        cur = xfs_inobt_init_cursor(mp, NULL, agbp, agno, btnum);
+        error = xfs_btree_count_blocks(cur, tree_blocks);
+        xfs_btree_del_cursor(cur, error ? XFS_BTREE_ERROR : XFS_BTREE_NOERROR);
+        xfs_buf_relse(agbp);
+
+        return error;
+}
+
+/*
+ * Figure out how many blocks to reserve and how many are used by this btree.
+ */
+int
+xfs_finobt_calc_reserves(
+        struct xfs_mount        *mp,
+        xfs_agnumber_t          agno,
+        xfs_extlen_t            *ask,
+        xfs_extlen_t            *used)
+{
+        xfs_extlen_t            tree_len = 0;
+        int                     error;
+
+        if (!xfs_sb_version_hasfinobt(&mp->m_sb))
+                return 0;
+
+        error = xfs_inobt_count_blocks(mp, agno, XFS_BTNUM_FINO, &tree_len);
+        if (error)
+                return error;
+
+        *ask += xfs_inobt_max_size(mp);
+        *used += tree_len;
+        return 0;
+}
diff --git a/fs/xfs/libxfs/xfs_ialloc_btree.h b/fs/xfs/libxfs/xfs_ialloc_btree.h
index bd88453217ce..aa81e2e63f3f 100644
--- a/fs/xfs/libxfs/xfs_ialloc_btree.h
+++ b/fs/xfs/libxfs/xfs_ialloc_btree.h
@@ -72,4 +72,7 @@ int xfs_inobt_rec_check_count(struct xfs_mount *,
 #define xfs_inobt_rec_check_count(mp, rec)      0
 #endif  /* DEBUG */
 
+int xfs_finobt_calc_reserves(struct xfs_mount *mp, xfs_agnumber_t agno,
+                xfs_extlen_t *ask, xfs_extlen_t *used);
+
 #endif  /* __XFS_IALLOC_BTREE_H__ */
diff --git a/fs/xfs/xfs_inode.c b/fs/xfs/xfs_inode.c
index b9557795eb74..de32f0fe47c8 100644
--- a/fs/xfs/xfs_inode.c
+++ b/fs/xfs/xfs_inode.c
@@ -1792,22 +1792,23 @@ xfs_inactive_ifree(
         int                     error;
 
         /*
-         * The ifree transaction might need to allocate blocks for record
-         * insertion to the finobt. We don't want to fail here at ENOSPC, so
-         * allow ifree to dip into the reserved block pool if necessary.
-         *
-         * Freeing large sets of inodes generally means freeing inode chunks,
-         * directory and file data blocks, so this should be relatively safe.
-         * Only under severe circumstances should it be possible to free enough
-         * inodes to exhaust the reserve block pool via finobt expansion while
-         * at the same time not creating free space in the filesystem.
+         * We try to use a per-AG reservation for any block needed by the finobt
+         * tree, but as the finobt feature predates the per-AG reservation
+         * support a degraded file system might not have enough space for the
+         * reservation at mount time.  In that case try to dip into the reserved
+         * pool and pray.
          *
          * Send a warning if the reservation does happen to fail, as the inode
          * now remains allocated and sits on the unlinked list until the fs is
          * repaired.
          */
-        error = xfs_trans_alloc(mp, &M_RES(mp)->tr_ifree,
-                        XFS_IFREE_SPACE_RES(mp), 0, XFS_TRANS_RESERVE, &tp);
+        if (unlikely(mp->m_inotbt_nores)) {
+                error = xfs_trans_alloc(mp, &M_RES(mp)->tr_ifree,
+                                XFS_IFREE_SPACE_RES(mp), 0, XFS_TRANS_RESERVE,
+                                &tp);
+        } else {
+                error = xfs_trans_alloc(mp, &M_RES(mp)->tr_ifree, 0, 0, 0, &tp);
+        }
         if (error) {
                 if (error == -ENOSPC) {
                         xfs_warn_ratelimited(mp,
diff --git a/fs/xfs/xfs_mount.h b/fs/xfs/xfs_mount.h
index 84f785218907..7f351f706b7a 100644
--- a/fs/xfs/xfs_mount.h
+++ b/fs/xfs/xfs_mount.h
@@ -140,6 +140,7 @@ typedef struct xfs_mount {
         int                     m_fixedfsid[2]; /* unchanged for life of FS */
         uint                    m_dmevmask;     /* DMI events for this FS */
         __uint64_t              m_flags;        /* global mount flags */
+        bool                    m_inotbt_nores; /* no per-AG finobt resv. */
         int                     m_ialloc_inos;  /* inodes in inode allocation */
         int                     m_ialloc_blks;  /* blocks in inode allocation */
         int                     m_ialloc_min_blks;/* min blocks in sparse inode