Add the rt linux 4.1.3-rt3 as base
[kvmfornfv.git] / kernel / fs / xfs / xfs_mount.c
diff --git a/kernel/fs/xfs/xfs_mount.c b/kernel/fs/xfs/xfs_mount.c
new file mode 100644 (file)
index 0000000..6f23fbd
--- /dev/null
@@ -0,0 +1,1283 @@
+/*
+ * Copyright (c) 2000-2005 Silicon Graphics, Inc.
+ * All Rights Reserved.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it would be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write the Free Software Foundation,
+ * Inc.,  51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+#include "xfs.h"
+#include "xfs_fs.h"
+#include "xfs_shared.h"
+#include "xfs_format.h"
+#include "xfs_log_format.h"
+#include "xfs_trans_resv.h"
+#include "xfs_bit.h"
+#include "xfs_sb.h"
+#include "xfs_mount.h"
+#include "xfs_da_format.h"
+#include "xfs_da_btree.h"
+#include "xfs_inode.h"
+#include "xfs_dir2.h"
+#include "xfs_ialloc.h"
+#include "xfs_alloc.h"
+#include "xfs_rtalloc.h"
+#include "xfs_bmap.h"
+#include "xfs_trans.h"
+#include "xfs_trans_priv.h"
+#include "xfs_log.h"
+#include "xfs_error.h"
+#include "xfs_quota.h"
+#include "xfs_fsops.h"
+#include "xfs_trace.h"
+#include "xfs_icache.h"
+#include "xfs_sysfs.h"
+
+
+static DEFINE_MUTEX(xfs_uuid_table_mutex);
+static int xfs_uuid_table_size;
+static uuid_t *xfs_uuid_table;
+
+/*
+ * See if the UUID is unique among mounted XFS filesystems.
+ * Mount fails if UUID is nil or a FS with the same UUID is already mounted.
+ */
+STATIC int
+xfs_uuid_mount(
+       struct xfs_mount        *mp)
+{
+       uuid_t                  *uuid = &mp->m_sb.sb_uuid;
+       int                     hole, i;
+
+       if (mp->m_flags & XFS_MOUNT_NOUUID)
+               return 0;
+
+       if (uuid_is_nil(uuid)) {
+               xfs_warn(mp, "Filesystem has nil UUID - can't mount");
+               return -EINVAL;
+       }
+
+       mutex_lock(&xfs_uuid_table_mutex);
+       for (i = 0, hole = -1; i < xfs_uuid_table_size; i++) {
+               if (uuid_is_nil(&xfs_uuid_table[i])) {
+                       hole = i;
+                       continue;
+               }
+               if (uuid_equal(uuid, &xfs_uuid_table[i]))
+                       goto out_duplicate;
+       }
+
+       if (hole < 0) {
+               xfs_uuid_table = kmem_realloc(xfs_uuid_table,
+                       (xfs_uuid_table_size + 1) * sizeof(*xfs_uuid_table),
+                       xfs_uuid_table_size  * sizeof(*xfs_uuid_table),
+                       KM_SLEEP);
+               hole = xfs_uuid_table_size++;
+       }
+       xfs_uuid_table[hole] = *uuid;
+       mutex_unlock(&xfs_uuid_table_mutex);
+
+       return 0;
+
+ out_duplicate:
+       mutex_unlock(&xfs_uuid_table_mutex);
+       xfs_warn(mp, "Filesystem has duplicate UUID %pU - can't mount", uuid);
+       return -EINVAL;
+}
+
+STATIC void
+xfs_uuid_unmount(
+       struct xfs_mount        *mp)
+{
+       uuid_t                  *uuid = &mp->m_sb.sb_uuid;
+       int                     i;
+
+       if (mp->m_flags & XFS_MOUNT_NOUUID)
+               return;
+
+       mutex_lock(&xfs_uuid_table_mutex);
+       for (i = 0; i < xfs_uuid_table_size; i++) {
+               if (uuid_is_nil(&xfs_uuid_table[i]))
+                       continue;
+               if (!uuid_equal(uuid, &xfs_uuid_table[i]))
+                       continue;
+               memset(&xfs_uuid_table[i], 0, sizeof(uuid_t));
+               break;
+       }
+       ASSERT(i < xfs_uuid_table_size);
+       mutex_unlock(&xfs_uuid_table_mutex);
+}
+
+
+STATIC void
+__xfs_free_perag(
+       struct rcu_head *head)
+{
+       struct xfs_perag *pag = container_of(head, struct xfs_perag, rcu_head);
+
+       ASSERT(atomic_read(&pag->pag_ref) == 0);
+       kmem_free(pag);
+}
+
+/*
+ * Free up the per-ag resources associated with the mount structure.
+ */
+STATIC void
+xfs_free_perag(
+       xfs_mount_t     *mp)
+{
+       xfs_agnumber_t  agno;
+       struct xfs_perag *pag;
+
+       for (agno = 0; agno < mp->m_sb.sb_agcount; agno++) {
+               spin_lock(&mp->m_perag_lock);
+               pag = radix_tree_delete(&mp->m_perag_tree, agno);
+               spin_unlock(&mp->m_perag_lock);
+               ASSERT(pag);
+               ASSERT(atomic_read(&pag->pag_ref) == 0);
+               call_rcu(&pag->rcu_head, __xfs_free_perag);
+       }
+}
+
+/*
+ * Check size of device based on the (data/realtime) block count.
+ * Note: this check is used by the growfs code as well as mount.
+ */
+int
+xfs_sb_validate_fsb_count(
+       xfs_sb_t        *sbp,
+       __uint64_t      nblocks)
+{
+       ASSERT(PAGE_SHIFT >= sbp->sb_blocklog);
+       ASSERT(sbp->sb_blocklog >= BBSHIFT);
+
+       /* Limited by ULONG_MAX of page cache index */
+       if (nblocks >> (PAGE_CACHE_SHIFT - sbp->sb_blocklog) > ULONG_MAX)
+               return -EFBIG;
+       return 0;
+}
+
+int
+xfs_initialize_perag(
+       xfs_mount_t     *mp,
+       xfs_agnumber_t  agcount,
+       xfs_agnumber_t  *maxagi)
+{
+       xfs_agnumber_t  index;
+       xfs_agnumber_t  first_initialised = 0;
+       xfs_perag_t     *pag;
+       xfs_agino_t     agino;
+       xfs_ino_t       ino;
+       xfs_sb_t        *sbp = &mp->m_sb;
+       int             error = -ENOMEM;
+
+       /*
+        * Walk the current per-ag tree so we don't try to initialise AGs
+        * that already exist (growfs case). Allocate and insert all the
+        * AGs we don't find ready for initialisation.
+        */
+       for (index = 0; index < agcount; index++) {
+               pag = xfs_perag_get(mp, index);
+               if (pag) {
+                       xfs_perag_put(pag);
+                       continue;
+               }
+               if (!first_initialised)
+                       first_initialised = index;
+
+               pag = kmem_zalloc(sizeof(*pag), KM_MAYFAIL);
+               if (!pag)
+                       goto out_unwind;
+               pag->pag_agno = index;
+               pag->pag_mount = mp;
+               spin_lock_init(&pag->pag_ici_lock);
+               mutex_init(&pag->pag_ici_reclaim_lock);
+               INIT_RADIX_TREE(&pag->pag_ici_root, GFP_ATOMIC);
+               spin_lock_init(&pag->pag_buf_lock);
+               pag->pag_buf_tree = RB_ROOT;
+
+               if (radix_tree_preload(GFP_NOFS))
+                       goto out_unwind;
+
+               spin_lock(&mp->m_perag_lock);
+               if (radix_tree_insert(&mp->m_perag_tree, index, pag)) {
+                       BUG();
+                       spin_unlock(&mp->m_perag_lock);
+                       radix_tree_preload_end();
+                       error = -EEXIST;
+                       goto out_unwind;
+               }
+               spin_unlock(&mp->m_perag_lock);
+               radix_tree_preload_end();
+       }
+
+       /*
+        * If we mount with the inode64 option, or no inode overflows
+        * the legacy 32-bit address space clear the inode32 option.
+        */
+       agino = XFS_OFFBNO_TO_AGINO(mp, sbp->sb_agblocks - 1, 0);
+       ino = XFS_AGINO_TO_INO(mp, agcount - 1, agino);
+
+       if ((mp->m_flags & XFS_MOUNT_SMALL_INUMS) && ino > XFS_MAXINUMBER_32)
+               mp->m_flags |= XFS_MOUNT_32BITINODES;
+       else
+               mp->m_flags &= ~XFS_MOUNT_32BITINODES;
+
+       if (mp->m_flags & XFS_MOUNT_32BITINODES)
+               index = xfs_set_inode32(mp, agcount);
+       else
+               index = xfs_set_inode64(mp, agcount);
+
+       if (maxagi)
+               *maxagi = index;
+       return 0;
+
+out_unwind:
+       kmem_free(pag);
+       for (; index > first_initialised; index--) {
+               pag = radix_tree_delete(&mp->m_perag_tree, index);
+               kmem_free(pag);
+       }
+       return error;
+}
+
+/*
+ * xfs_readsb
+ *
+ * Does the initial read of the superblock.
+ */
+int
+xfs_readsb(
+       struct xfs_mount *mp,
+       int             flags)
+{
+       unsigned int    sector_size;
+       struct xfs_buf  *bp;
+       struct xfs_sb   *sbp = &mp->m_sb;
+       int             error;
+       int             loud = !(flags & XFS_MFSI_QUIET);
+       const struct xfs_buf_ops *buf_ops;
+
+       ASSERT(mp->m_sb_bp == NULL);
+       ASSERT(mp->m_ddev_targp != NULL);
+
+       /*
+        * For the initial read, we must guess at the sector
+        * size based on the block device.  It's enough to
+        * get the sb_sectsize out of the superblock and
+        * then reread with the proper length.
+        * We don't verify it yet, because it may not be complete.
+        */
+       sector_size = xfs_getsize_buftarg(mp->m_ddev_targp);
+       buf_ops = NULL;
+
+       /*
+        * Allocate a (locked) buffer to hold the superblock.
+        * This will be kept around at all times to optimize
+        * access to the superblock.
+        */
+reread:
+       error = xfs_buf_read_uncached(mp->m_ddev_targp, XFS_SB_DADDR,
+                                  BTOBB(sector_size), 0, &bp, buf_ops);
+       if (error) {
+               if (loud)
+                       xfs_warn(mp, "SB validate failed with error %d.", error);
+               /* bad CRC means corrupted metadata */
+               if (error == -EFSBADCRC)
+                       error = -EFSCORRUPTED;
+               return error;
+       }
+
+       /*
+        * Initialize the mount structure from the superblock.
+        */
+       xfs_sb_from_disk(sbp, XFS_BUF_TO_SBP(bp));
+
+       /*
+        * If we haven't validated the superblock, do so now before we try
+        * to check the sector size and reread the superblock appropriately.
+        */
+       if (sbp->sb_magicnum != XFS_SB_MAGIC) {
+               if (loud)
+                       xfs_warn(mp, "Invalid superblock magic number");
+               error = -EINVAL;
+               goto release_buf;
+       }
+
+       /*
+        * We must be able to do sector-sized and sector-aligned IO.
+        */
+       if (sector_size > sbp->sb_sectsize) {
+               if (loud)
+                       xfs_warn(mp, "device supports %u byte sectors (not %u)",
+                               sector_size, sbp->sb_sectsize);
+               error = -ENOSYS;
+               goto release_buf;
+       }
+
+       if (buf_ops == NULL) {
+               /*
+                * Re-read the superblock so the buffer is correctly sized,
+                * and properly verified.
+                */
+               xfs_buf_relse(bp);
+               sector_size = sbp->sb_sectsize;
+               buf_ops = loud ? &xfs_sb_buf_ops : &xfs_sb_quiet_buf_ops;
+               goto reread;
+       }
+
+       xfs_reinit_percpu_counters(mp);
+
+       /* no need to be quiet anymore, so reset the buf ops */
+       bp->b_ops = &xfs_sb_buf_ops;
+
+       mp->m_sb_bp = bp;
+       xfs_buf_unlock(bp);
+       return 0;
+
+release_buf:
+       xfs_buf_relse(bp);
+       return error;
+}
+
+/*
+ * Update alignment values based on mount options and sb values
+ */
+STATIC int
+xfs_update_alignment(xfs_mount_t *mp)
+{
+       xfs_sb_t        *sbp = &(mp->m_sb);
+
+       if (mp->m_dalign) {
+               /*
+                * If stripe unit and stripe width are not multiples
+                * of the fs blocksize turn off alignment.
+                */
+               if ((BBTOB(mp->m_dalign) & mp->m_blockmask) ||
+                   (BBTOB(mp->m_swidth) & mp->m_blockmask)) {
+                       xfs_warn(mp,
+               "alignment check failed: sunit/swidth vs. blocksize(%d)",
+                               sbp->sb_blocksize);
+                       return -EINVAL;
+               } else {
+                       /*
+                        * Convert the stripe unit and width to FSBs.
+                        */
+                       mp->m_dalign = XFS_BB_TO_FSBT(mp, mp->m_dalign);
+                       if (mp->m_dalign && (sbp->sb_agblocks % mp->m_dalign)) {
+                               xfs_warn(mp,
+                       "alignment check failed: sunit/swidth vs. agsize(%d)",
+                                        sbp->sb_agblocks);
+                               return -EINVAL;
+                       } else if (mp->m_dalign) {
+                               mp->m_swidth = XFS_BB_TO_FSBT(mp, mp->m_swidth);
+                       } else {
+                               xfs_warn(mp,
+                       "alignment check failed: sunit(%d) less than bsize(%d)",
+                                        mp->m_dalign, sbp->sb_blocksize);
+                               return -EINVAL;
+                       }
+               }
+
+               /*
+                * Update superblock with new values
+                * and log changes
+                */
+               if (xfs_sb_version_hasdalign(sbp)) {
+                       if (sbp->sb_unit != mp->m_dalign) {
+                               sbp->sb_unit = mp->m_dalign;
+                               mp->m_update_sb = true;
+                       }
+                       if (sbp->sb_width != mp->m_swidth) {
+                               sbp->sb_width = mp->m_swidth;
+                               mp->m_update_sb = true;
+                       }
+               } else {
+                       xfs_warn(mp,
+       "cannot change alignment: superblock does not support data alignment");
+                       return -EINVAL;
+               }
+       } else if ((mp->m_flags & XFS_MOUNT_NOALIGN) != XFS_MOUNT_NOALIGN &&
+                   xfs_sb_version_hasdalign(&mp->m_sb)) {
+                       mp->m_dalign = sbp->sb_unit;
+                       mp->m_swidth = sbp->sb_width;
+       }
+
+       return 0;
+}
+
+/*
+ * 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;
+
+       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 {
+               mp->m_maxicount = 0;
+       }
+}
+
+/*
+ * 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;
+
+       if (!(mp->m_flags & XFS_MOUNT_DFLT_IOSIZE)) {
+               if (mp->m_flags & XFS_MOUNT_WSYNC) {
+                       readio_log = XFS_WSYNC_READIO_LOG;
+                       writeio_log = XFS_WSYNC_WRITEIO_LOG;
+               } else {
+                       readio_log = XFS_READIO_LOG_LARGE;
+                       writeio_log = XFS_WRITEIO_LOG_LARGE;
+               }
+       } else {
+               readio_log = mp->m_readio_log;
+               writeio_log = mp->m_writeio_log;
+       }
+
+       if (sbp->sb_blocklog > readio_log) {
+               mp->m_readio_log = sbp->sb_blocklog;
+       } else {
+               mp->m_readio_log = readio_log;
+       }
+       mp->m_readio_blocks = 1 << (mp->m_readio_log - sbp->sb_blocklog);
+       if (sbp->sb_blocklog > writeio_log) {
+               mp->m_writeio_log = sbp->sb_blocklog;
+       } else {
+               mp->m_writeio_log = writeio_log;
+       }
+       mp->m_writeio_blocks = 1 << (mp->m_writeio_log - sbp->sb_blocklog);
+}
+
+/*
+ * precalculate the low space thresholds for dynamic speculative preallocation.
+ */
+void
+xfs_set_low_space_thresholds(
+       struct xfs_mount        *mp)
+{
+       int i;
+
+       for (i = 0; i < XFS_LOWSP_MAX; i++) {
+               __uint64_t space = mp->m_sb.sb_dblocks;
+
+               do_div(space, 100);
+               mp->m_low_space[i] = space * (i + 1);
+       }
+}
+
+
+/*
+ * 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))
+               mp->m_inoalign_mask = mp->m_sb.sb_inoalignmt - 1;
+       else
+               mp->m_inoalign_mask = 0;
+       /*
+        * If we are using stripe alignment, check whether
+        * the stripe unit is a multiple of the inode alignment
+        */
+       if (mp->m_dalign && mp->m_inoalign_mask &&
+           !(mp->m_dalign & mp->m_inoalign_mask))
+               mp->m_sinoalign = mp->m_dalign;
+       else
+               mp->m_sinoalign = 0;
+}
+
+/*
+ * Check that the data (and log if separate) is an ok size.
+ */
+STATIC int
+xfs_check_sizes(
+       struct xfs_mount *mp)
+{
+       struct xfs_buf  *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) {
+               xfs_warn(mp, "filesystem size mismatch detected");
+               return -EFBIG;
+       }
+       error = xfs_buf_read_uncached(mp->m_ddev_targp,
+                                       d - XFS_FSS_TO_BB(mp, 1),
+                                       XFS_FSS_TO_BB(mp, 1), 0, &bp, NULL);
+       if (error) {
+               xfs_warn(mp, "last sector read failed");
+               return error;
+       }
+       xfs_buf_relse(bp);
+
+       if (mp->m_logdev_targp == mp->m_ddev_targp)
+               return 0;
+
+       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) {
+               xfs_warn(mp, "log size mismatch detected");
+               return -EFBIG;
+       }
+       error = xfs_buf_read_uncached(mp->m_logdev_targp,
+                                       d - XFS_FSB_TO_BB(mp, 1),
+                                       XFS_FSB_TO_BB(mp, 1), 0, &bp, NULL);
+       if (error) {
+               xfs_warn(mp, "log device read failed");
+               return error;
+       }
+       xfs_buf_relse(bp);
+       return 0;
+}
+
+/*
+ * Clear the quotaflags in memory and in the superblock.
+ */
+int
+xfs_mount_reset_sbqflags(
+       struct xfs_mount        *mp)
+{
+       mp->m_qflags = 0;
+
+       /* It is OK to look at sb_qflags in the mount path without m_sb_lock. */
+       if (mp->m_sb.sb_qflags == 0)
+               return 0;
+       spin_lock(&mp->m_sb_lock);
+       mp->m_sb.sb_qflags = 0;
+       spin_unlock(&mp->m_sb_lock);
+
+       if (!xfs_fs_writable(mp, SB_FREEZE_WRITE))
+               return 0;
+
+       return xfs_sync_sb(mp, false);
+}
+
+__uint64_t
+xfs_default_resblks(xfs_mount_t *mp)
+{
+       __uint64_t resblks;
+
+       /*
+        * We default to 5% or 8192 fsbs of space reserved, whichever is
+        * smaller.  This is intended to cover concurrent allocation
+        * transactions when we initially hit enospc. These each require a 4
+        * block reservation. Hence by default we cover roughly 2000 concurrent
+        * allocation reservations.
+        */
+       resblks = mp->m_sb.sb_dblocks;
+       do_div(resblks, 20);
+       resblks = min_t(__uint64_t, resblks, 8192);
+       return resblks;
+}
+
+/*
+ * 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)
+{
+       xfs_sb_t        *sbp = &(mp->m_sb);
+       xfs_inode_t     *rip;
+       __uint64_t      resblks;
+       uint            quotamount = 0;
+       uint            quotaflags = 0;
+       int             error = 0;
+
+       xfs_sb_mount_common(mp, sbp);
+
+       /*
+        * Check for a mismatched features2 values.  Older kernels read & wrote
+        * into the wrong sb offset for sb_features2 on some platforms due to
+        * xfs_sb_t not being 64bit size aligned when sb_features2 was added,
+        * which made older superblock reading/writing routines swap it as a
+        * 64-bit value.
+        *
+        * For backwards compatibility, we make both slots equal.
+        *
+        * If we detect a mismatched field, we OR the set bits into the existing
+        * features2 field in case it has already been modified; we don't want
+        * to lose any features.  We then update the bad location with the ORed
+        * value so that older kernels will see any features2 flags. The
+        * superblock writeback code ensures the new sb_features2 is copied to
+        * sb_bad_features2 before it is logged or written to disk.
+        */
+       if (xfs_sb_has_mismatched_features2(sbp)) {
+               xfs_warn(mp, "correcting sb_features alignment problem");
+               sbp->sb_features2 |= sbp->sb_bad_features2;
+               mp->m_update_sb = true;
+
+               /*
+                * Re-check for ATTR2 in case it was found in bad_features2
+                * slot.
+                */
+               if (xfs_sb_version_hasattr2(&mp->m_sb) &&
+                  !(mp->m_flags & XFS_MOUNT_NOATTR2))
+                       mp->m_flags |= XFS_MOUNT_ATTR2;
+       }
+
+       if (xfs_sb_version_hasattr2(&mp->m_sb) &&
+          (mp->m_flags & XFS_MOUNT_NOATTR2)) {
+               xfs_sb_version_removeattr2(&mp->m_sb);
+               mp->m_update_sb = true;
+
+               /* update sb_versionnum for the clearing of the morebits */
+               if (!sbp->sb_features2)
+                       mp->m_update_sb = true;
+       }
+
+       /* always use v2 inodes by default now */
+       if (!(mp->m_sb.sb_versionnum & XFS_SB_VERSION_NLINKBIT)) {
+               mp->m_sb.sb_versionnum |= XFS_SB_VERSION_NLINKBIT;
+               mp->m_update_sb = true;
+       }
+
+       /*
+        * 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);
+       if (error)
+               goto out;
+
+       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);
+
+       error = xfs_sysfs_init(&mp->m_kobj, &xfs_mp_ktype, NULL, mp->m_fsname);
+       if (error)
+               goto out;
+
+       error = xfs_uuid_mount(mp);
+       if (error)
+               goto out_remove_sysfs;
+
+       /*
+        * Set the minimum read and write sizes
+        */
+       xfs_set_rw_sizes(mp);
+
+       /* set the low space thresholds for dynamic preallocation */
+       xfs_set_low_space_thresholds(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.
+        *
+        * For v5 filesystems, scale the cluster size with the inode size to
+        * keep a constant ratio of inode per cluster buffer, but only if mkfs
+        * has set the inode alignment value appropriately for larger cluster
+        * sizes.
+        */
+       mp->m_inode_cluster_size = XFS_INODE_BIG_CLUSTER_SIZE;
+       if (xfs_sb_version_hascrc(&mp->m_sb)) {
+               int     new_size = mp->m_inode_cluster_size;
+
+               new_size *= mp->m_sb.sb_inodesize / XFS_DINODE_MIN_SIZE;
+               if (mp->m_sb.sb_inoalignmt >= XFS_B_TO_FSBT(mp, new_size))
+                       mp->m_inode_cluster_size = new_size;
+       }
+
+       /*
+        * Set inode alignment fields
+        */
+       xfs_set_inoalignment(mp);
+
+       /*
+        * Check that the data (and log if separate) is an ok size.
+        */
+       error = xfs_check_sizes(mp);
+       if (error)
+               goto out_remove_uuid;
+
+       /*
+        * Initialize realtime fields in the mount structure
+        */
+       error = xfs_rtmount_init(mp);
+       if (error) {
+               xfs_warn(mp, "RT mount failed");
+               goto out_remove_uuid;
+       }
+
+       /*
+        *  Copies the low order bits of the timestamp and the randomly
+        *  set "sequence" number out of a UUID.
+        */
+       uuid_getnodeuniq(&sbp->sb_uuid, mp->m_fixedfsid);
+
+       mp->m_dmevmask = 0;     /* not persistent; set after each mount */
+
+       error = xfs_da_mount(mp);
+       if (error) {
+               xfs_warn(mp, "Failed dir/attr init: %d", error);
+               goto out_remove_uuid;
+       }
+
+       /*
+        * Initialize the precomputed transaction reservations values.
+        */
+       xfs_trans_init(mp);
+
+       /*
+        * Allocate and initialize the per-ag data.
+        */
+       spin_lock_init(&mp->m_perag_lock);
+       INIT_RADIX_TREE(&mp->m_perag_tree, GFP_ATOMIC);
+       error = xfs_initialize_perag(mp, sbp->sb_agcount, &mp->m_maxagi);
+       if (error) {
+               xfs_warn(mp, "Failed per-ag init: %d", error);
+               goto out_free_dir;
+       }
+
+       if (!sbp->sb_logblocks) {
+               xfs_warn(mp, "no log defined");
+               XFS_ERROR_REPORT("xfs_mountfs", XFS_ERRLEVEL_LOW, mp);
+               error = -EFSCORRUPTED;
+               goto out_free_perag;
+       }
+
+       /*
+        * log's mount-time initialization. Perform 1st part recovery if needed
+        */
+       error = xfs_log_mount(mp, mp->m_logdev_targp,
+                             XFS_FSB_TO_DADDR(mp, sbp->sb_logstart),
+                             XFS_FSB_TO_BB(mp, sbp->sb_logblocks));
+       if (error) {
+               xfs_warn(mp, "log mount failed");
+               goto out_fail_wait;
+       }
+
+       /*
+        * Now the log is mounted, we know if it was an unclean shutdown or
+        * not. If it was, with the first phase of recovery has completed, we
+        * have consistent AG blocks on disk. We have not recovered EFIs yet,
+        * but they are recovered transactionally in the second recovery phase
+        * later.
+        *
+        * Hence we can safely re-initialise incore superblock counters from
+        * the per-ag data. These may not be correct if the filesystem was not
+        * cleanly unmounted, so we need to wait for recovery to finish before
+        * doing this.
+        *
+        * If the filesystem was cleanly unmounted, then we can trust the
+        * values in the superblock to be correct and we don't need to do
+        * anything here.
+        *
+        * If we are currently making the filesystem, the initialisation will
+        * fail as the perag data is in an undefined state.
+        */
+       if (xfs_sb_version_haslazysbcount(&mp->m_sb) &&
+           !XFS_LAST_UNMOUNT_WAS_CLEAN(mp) &&
+            !mp->m_sb.sb_inprogress) {
+               error = xfs_initialize_perag_data(mp, sbp->sb_agcount);
+               if (error)
+                       goto out_log_dealloc;
+       }
+
+       /*
+        * Get and sanity-check the root inode.
+        * Save the pointer to it in the mount structure.
+        */
+       error = xfs_iget(mp, NULL, sbp->sb_rootino, 0, XFS_ILOCK_EXCL, &rip);
+       if (error) {
+               xfs_warn(mp, "failed to read root inode");
+               goto out_log_dealloc;
+       }
+
+       ASSERT(rip != NULL);
+
+       if (unlikely(!S_ISDIR(rip->i_d.di_mode))) {
+               xfs_warn(mp, "corrupted root inode %llu: not a directory",
+                       (unsigned long long)rip->i_ino);
+               xfs_iunlock(rip, XFS_ILOCK_EXCL);
+               XFS_ERROR_REPORT("xfs_mountfs_int(2)", XFS_ERRLEVEL_LOW,
+                                mp);
+               error = -EFSCORRUPTED;
+               goto out_rele_rip;
+       }
+       mp->m_rootip = rip;     /* save it */
+
+       xfs_iunlock(rip, XFS_ILOCK_EXCL);
+
+       /*
+        * Initialize realtime inode pointers in the mount structure
+        */
+       error = xfs_rtmount_inodes(mp);
+       if (error) {
+               /*
+                * Free up the root inode.
+                */
+               xfs_warn(mp, "failed to read RT inodes");
+               goto out_rele_rip;
+       }
+
+       /*
+        * If this is a read-only mount defer the superblock updates until
+        * the next remount into writeable mode.  Otherwise we would never
+        * perform the update e.g. for the root filesystem.
+        */
+       if (mp->m_update_sb && !(mp->m_flags & XFS_MOUNT_RDONLY)) {
+               error = xfs_sync_sb(mp, false);
+               if (error) {
+                       xfs_warn(mp, "failed to write sb changes");
+                       goto out_rtunmount;
+               }
+       }
+
+       /*
+        * Initialise the XFS quota management subsystem for this mount
+        */
+       if (XFS_IS_QUOTA_RUNNING(mp)) {
+               error = xfs_qm_newmount(mp, &quotamount, &quotaflags);
+               if (error)
+                       goto out_rtunmount;
+       } else {
+               ASSERT(!XFS_IS_QUOTA_ON(mp));
+
+               /*
+                * If a file system had quotas running earlier, but decided to
+                * mount without -o uquota/pquota/gquota options, revoke the
+                * quotachecked license.
+                */
+               if (mp->m_sb.sb_qflags & XFS_ALL_QUOTA_ACCT) {
+                       xfs_notice(mp, "resetting quota flags");
+                       error = xfs_mount_reset_sbqflags(mp);
+                       if (error)
+                               goto out_rtunmount;
+               }
+       }
+
+       /*
+        * Finish recovering the file system.  This part needed to be
+        * delayed until after the root and real-time bitmap inodes
+        * were consistently read in.
+        */
+       error = xfs_log_mount_finish(mp);
+       if (error) {
+               xfs_warn(mp, "log mount finish failed");
+               goto out_rtunmount;
+       }
+
+       /*
+        * Complete the quota initialisation, post-log-replay component.
+        */
+       if (quotamount) {
+               ASSERT(mp->m_qflags == 0);
+               mp->m_qflags = quotaflags;
+
+               xfs_qm_mount_quotas(mp);
+       }
+
+       /*
+        * Now we are mounted, reserve a small amount of unused space for
+        * privileged transactions. This is needed so that transaction
+        * space required for critical operations can dip into this pool
+        * when at ENOSPC. This is needed for operations like create with
+        * attr, unwritten extent conversion at ENOSPC, etc. Data allocations
+        * are not allowed to use this reserved space.
+        *
+        * This may drive us straight to ENOSPC on mount, but that implies
+        * we were already there on the last unmount. Warn if this occurs.
+        */
+       if (!(mp->m_flags & XFS_MOUNT_RDONLY)) {
+               resblks = xfs_default_resblks(mp);
+               error = xfs_reserve_blocks(mp, &resblks, NULL);
+               if (error)
+                       xfs_warn(mp,
+       "Unable to allocate reserve blocks. Continuing without reserve pool.");
+       }
+
+       return 0;
+
+ out_rtunmount:
+       xfs_rtunmount_inodes(mp);
+ out_rele_rip:
+       IRELE(rip);
+ out_log_dealloc:
+       xfs_log_unmount(mp);
+ out_fail_wait:
+       if (mp->m_logdev_targp && mp->m_logdev_targp != mp->m_ddev_targp)
+               xfs_wait_buftarg(mp->m_logdev_targp);
+       xfs_wait_buftarg(mp->m_ddev_targp);
+ out_free_perag:
+       xfs_free_perag(mp);
+ out_free_dir:
+       xfs_da_unmount(mp);
+ out_remove_uuid:
+       xfs_uuid_unmount(mp);
+ out_remove_sysfs:
+       xfs_sysfs_del(&mp->m_kobj);
+ out:
+       return error;
+}
+
+/*
+ * This flushes out the inodes,dquots and the superblock, unmounts the
+ * log and makes sure that incore structures are freed.
+ */
+void
+xfs_unmountfs(
+       struct xfs_mount        *mp)
+{
+       __uint64_t              resblks;
+       int                     error;
+
+       cancel_delayed_work_sync(&mp->m_eofblocks_work);
+
+       xfs_qm_unmount_quotas(mp);
+       xfs_rtunmount_inodes(mp);
+       IRELE(mp->m_rootip);
+
+       /*
+        * We can potentially deadlock here if we have an inode cluster
+        * that has been freed has its buffer still pinned in memory because
+        * the transaction is still sitting in a iclog. The stale inodes
+        * on that buffer will have their flush locks held until the
+        * transaction hits the disk and the callbacks run. the inode
+        * flush takes the flush lock unconditionally and with nothing to
+        * push out the iclog we will never get that unlocked. hence we
+        * need to force the log first.
+        */
+       xfs_log_force(mp, XFS_LOG_SYNC);
+
+       /*
+        * Flush all pending changes from the AIL.
+        */
+       xfs_ail_push_all_sync(mp->m_ail);
+
+       /*
+        * And reclaim all inodes.  At this point there should be no dirty
+        * inodes and none should be pinned or locked, but use synchronous
+        * reclaim just to be sure. We can stop background inode reclaim
+        * here as well if it is still running.
+        */
+       cancel_delayed_work_sync(&mp->m_reclaim_work);
+       xfs_reclaim_inodes(mp, SYNC_WAIT);
+
+       xfs_qm_unmount(mp);
+
+       /*
+        * Unreserve any blocks we have so that when we unmount we don't account
+        * the reserved free space as used. This is really only necessary for
+        * lazy superblock counting because it trusts the incore superblock
+        * counters to be absolutely correct on clean unmount.
+        *
+        * We don't bother correcting this elsewhere for lazy superblock
+        * counting because on mount of an unclean filesystem we reconstruct the
+        * correct counter value and this is irrelevant.
+        *
+        * For non-lazy counter filesystems, this doesn't matter at all because
+        * we only every apply deltas to the superblock and hence the incore
+        * value does not matter....
+        */
+       resblks = 0;
+       error = xfs_reserve_blocks(mp, &resblks, NULL);
+       if (error)
+               xfs_warn(mp, "Unable to free reserved block pool. "
+                               "Freespace may not be correct on next mount.");
+
+       error = xfs_log_sbcount(mp);
+       if (error)
+               xfs_warn(mp, "Unable to update superblock counters. "
+                               "Freespace may not be correct on next mount.");
+
+       xfs_log_unmount(mp);
+       xfs_da_unmount(mp);
+       xfs_uuid_unmount(mp);
+
+#if defined(DEBUG)
+       xfs_errortag_clearall(mp, 0);
+#endif
+       xfs_free_perag(mp);
+
+       xfs_sysfs_del(&mp->m_kobj);
+}
+
+/*
+ * Determine whether modifications can proceed. The caller specifies the minimum
+ * freeze level for which modifications should not be allowed. This allows
+ * certain operations to proceed while the freeze sequence is in progress, if
+ * necessary.
+ */
+bool
+xfs_fs_writable(
+       struct xfs_mount        *mp,
+       int                     level)
+{
+       ASSERT(level > SB_UNFROZEN);
+       if ((mp->m_super->s_writers.frozen >= level) ||
+           XFS_FORCED_SHUTDOWN(mp) || (mp->m_flags & XFS_MOUNT_RDONLY))
+               return false;
+
+       return true;
+}
+
+/*
+ * xfs_log_sbcount
+ *
+ * Sync the superblock counters to disk.
+ *
+ * Note this code can be called during the process of freezing, so we use the
+ * transaction allocator that does not block when the transaction subsystem is
+ * in its frozen state.
+ */
+int
+xfs_log_sbcount(xfs_mount_t *mp)
+{
+       /* allow this to proceed during the freeze sequence... */
+       if (!xfs_fs_writable(mp, SB_FREEZE_COMPLETE))
+               return 0;
+
+       /*
+        * we don't need to do this if we are updating the superblock
+        * counters on every modification.
+        */
+       if (!xfs_sb_version_haslazysbcount(&mp->m_sb))
+               return 0;
+
+       return xfs_sync_sb(mp, true);
+}
+
+/*
+ * Deltas for the inode count are +/-64, hence we use a large batch size
+ * of 128 so we don't need to take the counter lock on every update.
+ */
+#define XFS_ICOUNT_BATCH       128
+int
+xfs_mod_icount(
+       struct xfs_mount        *mp,
+       int64_t                 delta)
+{
+       __percpu_counter_add(&mp->m_icount, delta, XFS_ICOUNT_BATCH);
+       if (__percpu_counter_compare(&mp->m_icount, 0, XFS_ICOUNT_BATCH) < 0) {
+               ASSERT(0);
+               percpu_counter_add(&mp->m_icount, -delta);
+               return -EINVAL;
+       }
+       return 0;
+}
+
+int
+xfs_mod_ifree(
+       struct xfs_mount        *mp,
+       int64_t                 delta)
+{
+       percpu_counter_add(&mp->m_ifree, delta);
+       if (percpu_counter_compare(&mp->m_ifree, 0) < 0) {
+               ASSERT(0);
+               percpu_counter_add(&mp->m_ifree, -delta);
+               return -EINVAL;
+       }
+       return 0;
+}
+
+/*
+ * Deltas for the block count can vary from 1 to very large, but lock contention
+ * only occurs on frequent small block count updates such as in the delayed
+ * allocation path for buffered writes (page a time updates). Hence we set
+ * a large batch count (1024) to minimise global counter updates except when
+ * we get near to ENOSPC and we have to be very accurate with our updates.
+ */
+#define XFS_FDBLOCKS_BATCH     1024
+int
+xfs_mod_fdblocks(
+       struct xfs_mount        *mp,
+       int64_t                 delta,
+       bool                    rsvd)
+{
+       int64_t                 lcounter;
+       long long               res_used;
+       s32                     batch;
+
+       if (delta > 0) {
+               /*
+                * If the reserve pool is depleted, put blocks back into it
+                * first. Most of the time the pool is full.
+                */
+               if (likely(mp->m_resblks == mp->m_resblks_avail)) {
+                       percpu_counter_add(&mp->m_fdblocks, delta);
+                       return 0;
+               }
+
+               spin_lock(&mp->m_sb_lock);
+               res_used = (long long)(mp->m_resblks - mp->m_resblks_avail);
+
+               if (res_used > delta) {
+                       mp->m_resblks_avail += delta;
+               } else {
+                       delta -= res_used;
+                       mp->m_resblks_avail = mp->m_resblks;
+                       percpu_counter_add(&mp->m_fdblocks, delta);
+               }
+               spin_unlock(&mp->m_sb_lock);
+               return 0;
+       }
+
+       /*
+        * Taking blocks away, need to be more accurate the closer we
+        * are to zero.
+        *
+        * If the counter has a value of less than 2 * max batch size,
+        * then make everything serialise as we are real close to
+        * ENOSPC.
+        */
+       if (__percpu_counter_compare(&mp->m_fdblocks, 2 * XFS_FDBLOCKS_BATCH,
+                                    XFS_FDBLOCKS_BATCH) < 0)
+               batch = 1;
+       else
+               batch = XFS_FDBLOCKS_BATCH;
+
+       __percpu_counter_add(&mp->m_fdblocks, delta, batch);
+       if (__percpu_counter_compare(&mp->m_fdblocks, XFS_ALLOC_SET_ASIDE(mp),
+                                    XFS_FDBLOCKS_BATCH) >= 0) {
+               /* we had space! */
+               return 0;
+       }
+
+       /*
+        * lock up the sb for dipping into reserves before releasing the space
+        * that took us to ENOSPC.
+        */
+       spin_lock(&mp->m_sb_lock);
+       percpu_counter_add(&mp->m_fdblocks, -delta);
+       if (!rsvd)
+               goto fdblocks_enospc;
+
+       lcounter = (long long)mp->m_resblks_avail + delta;
+       if (lcounter >= 0) {
+               mp->m_resblks_avail = lcounter;
+               spin_unlock(&mp->m_sb_lock);
+               return 0;
+       }
+       printk_once(KERN_WARNING
+               "Filesystem \"%s\": reserve blocks depleted! "
+               "Consider increasing reserve pool size.",
+               mp->m_fsname);
+fdblocks_enospc:
+       spin_unlock(&mp->m_sb_lock);
+       return -ENOSPC;
+}
+
+int
+xfs_mod_frextents(
+       struct xfs_mount        *mp,
+       int64_t                 delta)
+{
+       int64_t                 lcounter;
+       int                     ret = 0;
+
+       spin_lock(&mp->m_sb_lock);
+       lcounter = mp->m_sb.sb_frextents + delta;
+       if (lcounter < 0)
+               ret = -ENOSPC;
+       else
+               mp->m_sb.sb_frextents = lcounter;
+       spin_unlock(&mp->m_sb_lock);
+       return ret;
+}
+
+/*
+ * xfs_getsb() is called to obtain the buffer for the superblock.
+ * The buffer is returned locked and read in from disk.
+ * The buffer should be released with a call to xfs_brelse().
+ *
+ * If the flags parameter is BUF_TRYLOCK, then we'll only return
+ * the superblock buffer if it can be locked without sleeping.
+ * If it can't then we'll return NULL.
+ */
+struct xfs_buf *
+xfs_getsb(
+       struct xfs_mount        *mp,
+       int                     flags)
+{
+       struct xfs_buf          *bp = mp->m_sb_bp;
+
+       if (!xfs_buf_trylock(bp)) {
+               if (flags & XBF_TRYLOCK)
+                       return NULL;
+               xfs_buf_lock(bp);
+       }
+
+       xfs_buf_hold(bp);
+       ASSERT(XFS_BUF_ISDONE(bp));
+       return bp;
+}
+
+/*
+ * Used to free the superblock along various error paths.
+ */
+void
+xfs_freesb(
+       struct xfs_mount        *mp)
+{
+       struct xfs_buf          *bp = mp->m_sb_bp;
+
+       xfs_buf_lock(bp);
+       mp->m_sb_bp = NULL;
+       xfs_buf_relse(bp);
+}
+
+/*
+ * If the underlying (data/log/rt) device is readonly, there are some
+ * operations that cannot proceed.
+ */
+int
+xfs_dev_is_read_only(
+       struct xfs_mount        *mp,
+       char                    *message)
+{
+       if (xfs_readonly_buftarg(mp->m_ddev_targp) ||
+           xfs_readonly_buftarg(mp->m_logdev_targp) ||
+           (mp->m_rtdev_targp && xfs_readonly_buftarg(mp->m_rtdev_targp))) {
+               xfs_notice(mp, "%s required on read-only device.", message);
+               xfs_notice(mp, "write access unavailable, cannot proceed.");
+               return -EROFS;
+       }
+       return 0;
+}