[XFS] Refactor xfs_mountfs

Refactoring xfs_mountfs() to call sub-functions for logical chunks can
help save a bit of stack, and can make it easier to read this long
function.

The mount path is one of the longest common callchains, easily getting to
within a few bytes of the end of a 4k stack when over lvm, quotas are
enabled, and quotacheck must be done.

With this change on top of the other stack-related changes I've sent, I
can get xfs to survive a normal xfsqa run on 4k stacks over lvm.

SGI-PV: 971186
SGI-Modid: xfs-linux-melb:xfs-kern:29834a

Signed-off-by: Eric Sandeen <sandeen@sandeen.net>
Signed-off-by: Donald Douwsma <donaldd@sgi.com>
Signed-off-by: Tim Shimmin <tes@sgi.com>

1 files changed, 162 insertions, 105 deletions

diff --git a/fs/xfs/xfs_mount.c b/fs/xfs/xfs_mount.c
index 6115f371663d..2806d43d7d23 100644
--- a/fs/xfs/xfs_mount.c
+++ b/fs/xfs/xfs_mount.c
@@ -733,49 +733,13 @@ xfs_initialize_perag_data(xfs_mount_t *mp, xfs_agnumber_t agcount)
 }
 
 /*
- * xfs_mountfs
- *
- * This function does the following on an initial mount of a file system:
- *      - reads the superblock from disk and init the mount struct
- *      - if we're a 32-bit kernel, do a size check on the superblock
- *              so we don't mount terabyte filesystems
- *      - init mount struct realtime fields
- *      - allocate inode hash table for fs
- *      - init directory manager
- *      - perform recovery and init the log manager
+ * Update alignment values based on mount options and sb values
  */
-int
-xfs_mountfs(
-        xfs_mount_t     *mp,
-        int             mfsi_flags)
+STATIC int
+xfs_update_alignment(xfs_mount_t *mp, int mfsi_flags, __uint64_t *update_flags)
 {
-        xfs_buf_t       *bp;
         xfs_sb_t        *sbp = &(mp->m_sb);
-        xfs_inode_t     *rip;
-        bhv_vnode_t     *rvp = NULL;
-        int             readio_log, writeio_log;
-        xfs_daddr_t     d;
-        __uint64_t      resblks;
-        __int64_t       update_flags;
-        uint            quotamount, quotaflags;
-        int             agno;
-        int             uuid_mounted = 0;
-        int             error = 0;
 
-        if (mp->m_sb_bp == NULL) {
-                if ((error = xfs_readsb(mp, mfsi_flags))) {
-                        return error;
-                }
-        }
-        xfs_mount_common(mp, sbp);
-
-        /*
-         * Check if sb_agblocks is aligned at stripe boundary
-         * If sb_agblocks is NOT aligned turn off m_dalign since
-         * allocator alignment is within an ag, therefore ag has
-         * to be aligned at stripe boundary.
-         */
-        update_flags = 0LL;
         if (mp->m_dalign && !(mfsi_flags & XFS_MFSI_SECOND)) {
                 /*
                  * If stripe unit and stripe width are not multiples
@@ -786,8 +750,7 @@ xfs_mountfs(
                         if (mp->m_flags & XFS_MOUNT_RETERR) {
                                 cmn_err(CE_WARN,
                                         "XFS: alignment check 1 failed");
-                                error = XFS_ERROR(EINVAL);
-                                goto error1;
+                                return XFS_ERROR(EINVAL);
                         }
                         mp->m_dalign = mp->m_swidth = 0;
                 } else {
@@ -797,8 +760,7 @@ xfs_mountfs(
                         mp->m_dalign = XFS_BB_TO_FSBT(mp, mp->m_dalign);
                         if (mp->m_dalign && (sbp->sb_agblocks % mp->m_dalign)) {
                                 if (mp->m_flags & XFS_MOUNT_RETERR) {
-                                        error = XFS_ERROR(EINVAL);
-                                        goto error1;
+                                        return XFS_ERROR(EINVAL);
                                 }
                                 xfs_fs_cmn_err(CE_WARN, mp,
 "stripe alignment turned off: sunit(%d)/swidth(%d) incompatible with agsize(%d)",
@@ -815,8 +777,7 @@ xfs_mountfs(
 "stripe alignment turned off: sunit(%d) less than bsize(%d)",
                                                 mp->m_dalign,
                                                 mp->m_blockmask +1);
-                                        error = XFS_ERROR(EINVAL);
-                                        goto error1;
+                                        return XFS_ERROR(EINVAL);
                                 }
                                 mp->m_swidth = 0;
                         }
@@ -829,11 +790,11 @@ xfs_mountfs(
                 if (XFS_SB_VERSION_HASDALIGN(sbp)) {
                         if (sbp->sb_unit != mp->m_dalign) {
                                 sbp->sb_unit = mp->m_dalign;
-                                update_flags |= XFS_SB_UNIT;
+                                *update_flags |= XFS_SB_UNIT;
                         }
                         if (sbp->sb_width != mp->m_swidth) {
                                 sbp->sb_width = mp->m_swidth;
-                                update_flags |= XFS_SB_WIDTH;
+                                *update_flags |= XFS_SB_WIDTH;
                         }
                 }
         } else if ((mp->m_flags & XFS_MOUNT_NOALIGN) != XFS_MOUNT_NOALIGN &&
@@ -842,49 +803,45 @@ xfs_mountfs(
                         mp->m_swidth = sbp->sb_width;
         }
 
-        xfs_alloc_compute_maxlevels(mp);
-        xfs_bmap_compute_maxlevels(mp, XFS_DATA_FORK);
-        xfs_bmap_compute_maxlevels(mp, XFS_ATTR_FORK);
-        xfs_ialloc_compute_maxlevels(mp);
+        return 0;
+}
 
-        if (sbp->sb_imax_pct) {
-                __uint64_t      icount;
+/*
+ * Set the maximum inode count for this filesystem
+ */
+STATIC void
+xfs_set_maxicount(xfs_mount_t *mp)
+{
+        xfs_sb_t        *sbp = &(mp->m_sb);
+        __uint64_t      icount;
 
-                /* Make sure the maximum inode count is a multiple of the
-                 * units we allocate inodes in.
+        if (sbp->sb_imax_pct) {
+                /*
+                 * Make sure the maximum inode count is a multiple
+                 * of the units we allocate inodes in.
                  */
-
                 icount = sbp->sb_dblocks * sbp->sb_imax_pct;
                 do_div(icount, 100);
                 do_div(icount, mp->m_ialloc_blks);
                 mp->m_maxicount = (icount * mp->m_ialloc_blks)  <<
                                    sbp->sb_inopblog;
-        } else
+        } else {
                 mp->m_maxicount = 0;
-
-        mp->m_maxioffset = xfs_max_file_offset(sbp->sb_blocklog);
-
-        /*
-         * XFS uses the uuid from the superblock as the unique
-         * identifier for fsid.  We can not use the uuid from the volume
-         * since a single partition filesystem is identical to a single
-         * partition volume/filesystem.
-         */
-        if ((mfsi_flags & XFS_MFSI_SECOND) == 0 &&
-            (mp->m_flags & XFS_MOUNT_NOUUID) == 0) {
-                if (xfs_uuid_mount(mp)) {
-                        error = XFS_ERROR(EINVAL);
-                        goto error1;
-                }
-                uuid_mounted=1;
         }
+}
+
+/*
+ * Set the default minimum read and write sizes unless
+ * already specified in a mount option.
+ * We use smaller I/O sizes when the file system
+ * is being used for NFS service (wsync mount option).
+ */
+STATIC void
+xfs_set_rw_sizes(xfs_mount_t *mp)
+{
+        xfs_sb_t        *sbp = &(mp->m_sb);
+        int             readio_log, writeio_log;
 
-        /*
-         * Set the default minimum read and write sizes unless
-         * already specified in a mount option.
-         * We use smaller I/O sizes when the file system
-         * is being used for NFS service (wsync mount option).
-         */
         if (!(mp->m_flags & XFS_MOUNT_DFLT_IOSIZE)) {
                 if (mp->m_flags & XFS_MOUNT_WSYNC) {
                         readio_log = XFS_WSYNC_READIO_LOG;
@@ -910,17 +867,14 @@ xfs_mountfs(
                 mp->m_writeio_log = writeio_log;
         }
         mp->m_writeio_blocks = 1 << (mp->m_writeio_log - sbp->sb_blocklog);
+}
 
-        /*
-         * Set the inode cluster size.
-         * This may still be overridden by the file system
-         * block size if it is larger than the chosen cluster size.
-         */
-        mp->m_inode_cluster_size = XFS_INODE_BIG_CLUSTER_SIZE;
-
-        /*
-         * Set whether we're using inode alignment.
-         */
+/*
+ * Set whether we're using inode alignment.
+ */
+STATIC void
+xfs_set_inoalignment(xfs_mount_t *mp)
+{
         if (XFS_SB_VERSION_HASALIGN(&mp->m_sb) &&
             mp->m_sb.sb_inoalignmt >=
             XFS_B_TO_FSBT(mp, mp->m_inode_cluster_size))
@@ -936,14 +890,22 @@ xfs_mountfs(
                 mp->m_sinoalign = mp->m_dalign;
         else
                 mp->m_sinoalign = 0;
-        /*
-         * Check that the data (and log if separate) are an ok size.
-         */
+}
+
+/*
+ * Check that the data (and log if separate) are an ok size.
+ */
+STATIC int
+xfs_check_sizes(xfs_mount_t *mp, int mfsi_flags)
+{
+        xfs_buf_t       *bp;
+        xfs_daddr_t     d;
+        int             error;
+
         d = (xfs_daddr_t)XFS_FSB_TO_BB(mp, mp->m_sb.sb_dblocks);
         if (XFS_BB_TO_FSB(mp, d) != mp->m_sb.sb_dblocks) {
                 cmn_err(CE_WARN, "XFS: size check 1 failed");
-                error = XFS_ERROR(E2BIG);
-                goto error1;
+                return XFS_ERROR(E2BIG);
         }
         error = xfs_read_buf(mp, mp->m_ddev_targp,
                              d - XFS_FSS_TO_BB(mp, 1),
@@ -952,10 +914,9 @@ xfs_mountfs(
                 xfs_buf_relse(bp);
         } else {
                 cmn_err(CE_WARN, "XFS: size check 2 failed");
-                if (error == ENOSPC) {
+                if (error == ENOSPC)
                         error = XFS_ERROR(E2BIG);
-                }
-                goto error1;
+                return error;
         }
 
         if (((mfsi_flags & XFS_MFSI_CLIENT) == 0) &&
@@ -963,8 +924,7 @@ xfs_mountfs(
                 d = (xfs_daddr_t)XFS_FSB_TO_BB(mp, mp->m_sb.sb_logblocks);
                 if (XFS_BB_TO_FSB(mp, d) != mp->m_sb.sb_logblocks) {
                         cmn_err(CE_WARN, "XFS: size check 3 failed");
-                        error = XFS_ERROR(E2BIG);
-                        goto error1;
+                        return XFS_ERROR(E2BIG);
                 }
                 error = xfs_read_buf(mp, mp->m_logdev_targp,
                                      d - XFS_FSB_TO_BB(mp, 1),
@@ -973,17 +933,111 @@ xfs_mountfs(
                         xfs_buf_relse(bp);
                 } else {
                         cmn_err(CE_WARN, "XFS: size check 3 failed");
-                        if (error == ENOSPC) {
+                        if (error == ENOSPC)
                                 error = XFS_ERROR(E2BIG);
-                        }
+                        return error;
+                }
+        }
+        return 0;
+}
+
+/*
+ * xfs_mountfs
+ *
+ * This function does the following on an initial mount of a file system:
+ *      - reads the superblock from disk and init the mount struct
+ *      - if we're a 32-bit kernel, do a size check on the superblock
+ *              so we don't mount terabyte filesystems
+ *      - init mount struct realtime fields
+ *      - allocate inode hash table for fs
+ *      - init directory manager
+ *      - perform recovery and init the log manager
+ */
+int
+xfs_mountfs(
+        xfs_mount_t     *mp,
+        int             mfsi_flags)
+{
+        xfs_sb_t        *sbp = &(mp->m_sb);
+        xfs_inode_t     *rip;
+        bhv_vnode_t     *rvp = NULL;
+        __uint64_t      resblks;
+        __int64_t       update_flags = 0LL;
+        uint            quotamount, quotaflags;
+        int             agno;
+        int             uuid_mounted = 0;
+        int             error = 0;
+
+        if (mp->m_sb_bp == NULL) {
+                error = xfs_readsb(mp, mfsi_flags);
+                if (error)
+                        return error;
+        }
+        xfs_mount_common(mp, sbp);
+
+        /*
+         * Check if sb_agblocks is aligned at stripe boundary
+         * If sb_agblocks is NOT aligned turn off m_dalign since
+         * allocator alignment is within an ag, therefore ag has
+         * to be aligned at stripe boundary.
+         */
+        error = xfs_update_alignment(mp, mfsi_flags, &update_flags);
+        if (error)
+                goto error1;
+
+        xfs_alloc_compute_maxlevels(mp);
+        xfs_bmap_compute_maxlevels(mp, XFS_DATA_FORK);
+        xfs_bmap_compute_maxlevels(mp, XFS_ATTR_FORK);
+        xfs_ialloc_compute_maxlevels(mp);
+
+        xfs_set_maxicount(mp);
+
+        mp->m_maxioffset = xfs_max_file_offset(sbp->sb_blocklog);
+
+        /*
+         * XFS uses the uuid from the superblock as the unique
+         * identifier for fsid.  We can not use the uuid from the volume
+         * since a single partition filesystem is identical to a single
+         * partition volume/filesystem.
+         */
+        if ((mfsi_flags & XFS_MFSI_SECOND) == 0 &&
+            (mp->m_flags & XFS_MOUNT_NOUUID) == 0) {
+                if (xfs_uuid_mount(mp)) {
+                        error = XFS_ERROR(EINVAL);
                         goto error1;
                 }
+                uuid_mounted=1;
         }
 
         /*
+         * Set the minimum read and write sizes
+         */
+        xfs_set_rw_sizes(mp);
+
+        /*
+         * Set the inode cluster size.
+         * This may still be overridden by the file system
+         * block size if it is larger than the chosen cluster size.
+         */
+        mp->m_inode_cluster_size = XFS_INODE_BIG_CLUSTER_SIZE;
+
+        /*
+         * Set inode alignment fields
+         */
+        xfs_set_inoalignment(mp);
+
+        /*
+         * Check that the data (and log if separate) are an ok size.
+         */
+        error = xfs_check_sizes(mp, mfsi_flags);
+        if (error)
+                goto error1;
+
+        /*
          * Initialize realtime fields in the mount structure
          */
-        if ((error = xfs_rtmount_init(mp))) {
+        error = xfs_rtmount_init(mp);
+        if (error) {
                 cmn_err(CE_WARN, "XFS: RT mount failed");
                 goto error1;
         }
@@ -1101,7 +1155,8 @@ xfs_mountfs(
         /*
          * Initialize realtime inode pointers in the mount structure
          */
-        if ((error = xfs_rtmount_inodes(mp))) {
+        error = xfs_rtmount_inodes(mp);
+        if (error) {
                 /*
                  * Free up the root inode.
                  */
@@ -1119,7 +1174,8 @@ xfs_mountfs(
         /*
          * Initialise the XFS quota management subsystem for this mount
          */
-        if ((error = XFS_QM_INIT(mp, &quotamount, &quotaflags)))
+        error = XFS_QM_INIT(mp, &quotamount, &quotaflags);
+        if (error)
                 goto error4;
 
         /*
@@ -1136,7 +1192,8 @@ xfs_mountfs(
         /*
          * Complete the quota initialisation, post-log-replay component.
          */
-        if ((error = XFS_QM_MOUNT(mp, quotamount, quotaflags, mfsi_flags)))
+        error = XFS_QM_MOUNT(mp, quotamount, quotaflags, mfsi_flags);
+        if (error)
                 goto error4;
 
         /*