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-rw-r--r--fs/xfs/xfs_filestream.c771
1 files changed, 771 insertions, 0 deletions
diff --git a/fs/xfs/xfs_filestream.c b/fs/xfs/xfs_filestream.c
new file mode 100644
index 00000000000..ce2278611bb
--- /dev/null
+++ b/fs/xfs/xfs_filestream.c
@@ -0,0 +1,771 @@
+/*
+ * Copyright (c) 2006-2007 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_bmap_btree.h"
+#include "xfs_inum.h"
+#include "xfs_dir2.h"
+#include "xfs_dir2_sf.h"
+#include "xfs_attr_sf.h"
+#include "xfs_dinode.h"
+#include "xfs_inode.h"
+#include "xfs_ag.h"
+#include "xfs_dmapi.h"
+#include "xfs_log.h"
+#include "xfs_trans.h"
+#include "xfs_sb.h"
+#include "xfs_mount.h"
+#include "xfs_bmap.h"
+#include "xfs_alloc.h"
+#include "xfs_utils.h"
+#include "xfs_mru_cache.h"
+#include "xfs_filestream.h"
+
+#ifdef XFS_FILESTREAMS_TRACE
+
+ktrace_t *xfs_filestreams_trace_buf;
+
+STATIC void
+xfs_filestreams_trace(
+ xfs_mount_t *mp, /* mount point */
+ int type, /* type of trace */
+ const char *func, /* source function */
+ int line, /* source line number */
+ __psunsigned_t arg0,
+ __psunsigned_t arg1,
+ __psunsigned_t arg2,
+ __psunsigned_t arg3,
+ __psunsigned_t arg4,
+ __psunsigned_t arg5)
+{
+ ktrace_enter(xfs_filestreams_trace_buf,
+ (void *)(__psint_t)(type | (line << 16)),
+ (void *)func,
+ (void *)(__psunsigned_t)current_pid(),
+ (void *)mp,
+ (void *)(__psunsigned_t)arg0,
+ (void *)(__psunsigned_t)arg1,
+ (void *)(__psunsigned_t)arg2,
+ (void *)(__psunsigned_t)arg3,
+ (void *)(__psunsigned_t)arg4,
+ (void *)(__psunsigned_t)arg5,
+ NULL, NULL, NULL, NULL, NULL, NULL);
+}
+
+#define TRACE0(mp,t) TRACE6(mp,t,0,0,0,0,0,0)
+#define TRACE1(mp,t,a0) TRACE6(mp,t,a0,0,0,0,0,0)
+#define TRACE2(mp,t,a0,a1) TRACE6(mp,t,a0,a1,0,0,0,0)
+#define TRACE3(mp,t,a0,a1,a2) TRACE6(mp,t,a0,a1,a2,0,0,0)
+#define TRACE4(mp,t,a0,a1,a2,a3) TRACE6(mp,t,a0,a1,a2,a3,0,0)
+#define TRACE5(mp,t,a0,a1,a2,a3,a4) TRACE6(mp,t,a0,a1,a2,a3,a4,0)
+#define TRACE6(mp,t,a0,a1,a2,a3,a4,a5) \
+ xfs_filestreams_trace(mp, t, __FUNCTION__, __LINE__, \
+ (__psunsigned_t)a0, (__psunsigned_t)a1, \
+ (__psunsigned_t)a2, (__psunsigned_t)a3, \
+ (__psunsigned_t)a4, (__psunsigned_t)a5)
+
+#define TRACE_AG_SCAN(mp, ag, ag2) \
+ TRACE2(mp, XFS_FSTRM_KTRACE_AGSCAN, ag, ag2);
+#define TRACE_AG_PICK1(mp, max_ag, maxfree) \
+ TRACE2(mp, XFS_FSTRM_KTRACE_AGPICK1, max_ag, maxfree);
+#define TRACE_AG_PICK2(mp, ag, ag2, cnt, free, scan, flag) \
+ TRACE6(mp, XFS_FSTRM_KTRACE_AGPICK2, ag, ag2, \
+ cnt, free, scan, flag)
+#define TRACE_UPDATE(mp, ip, ag, cnt, ag2, cnt2) \
+ TRACE5(mp, XFS_FSTRM_KTRACE_UPDATE, ip, ag, cnt, ag2, cnt2)
+#define TRACE_FREE(mp, ip, pip, ag, cnt) \
+ TRACE4(mp, XFS_FSTRM_KTRACE_FREE, ip, pip, ag, cnt)
+#define TRACE_LOOKUP(mp, ip, pip, ag, cnt) \
+ TRACE4(mp, XFS_FSTRM_KTRACE_ITEM_LOOKUP, ip, pip, ag, cnt)
+#define TRACE_ASSOCIATE(mp, ip, pip, ag, cnt) \
+ TRACE4(mp, XFS_FSTRM_KTRACE_ASSOCIATE, ip, pip, ag, cnt)
+#define TRACE_MOVEAG(mp, ip, pip, oag, ocnt, nag, ncnt) \
+ TRACE6(mp, XFS_FSTRM_KTRACE_MOVEAG, ip, pip, oag, ocnt, nag, ncnt)
+#define TRACE_ORPHAN(mp, ip, ag) \
+ TRACE2(mp, XFS_FSTRM_KTRACE_ORPHAN, ip, ag);
+
+
+#else
+#define TRACE_AG_SCAN(mp, ag, ag2)
+#define TRACE_AG_PICK1(mp, max_ag, maxfree)
+#define TRACE_AG_PICK2(mp, ag, ag2, cnt, free, scan, flag)
+#define TRACE_UPDATE(mp, ip, ag, cnt, ag2, cnt2)
+#define TRACE_FREE(mp, ip, pip, ag, cnt)
+#define TRACE_LOOKUP(mp, ip, pip, ag, cnt)
+#define TRACE_ASSOCIATE(mp, ip, pip, ag, cnt)
+#define TRACE_MOVEAG(mp, ip, pip, oag, ocnt, nag, ncnt)
+#define TRACE_ORPHAN(mp, ip, ag)
+#endif
+
+static kmem_zone_t *item_zone;
+
+/*
+ * Structure for associating a file or a directory with an allocation group.
+ * The parent directory pointer is only needed for files, but since there will
+ * generally be vastly more files than directories in the cache, using the same
+ * data structure simplifies the code with very little memory overhead.
+ */
+typedef struct fstrm_item
+{
+ xfs_agnumber_t ag; /* AG currently in use for the file/directory. */
+ xfs_inode_t *ip; /* inode self-pointer. */
+ xfs_inode_t *pip; /* Parent directory inode pointer. */
+} fstrm_item_t;
+
+
+/*
+ * Scan the AGs starting at startag looking for an AG that isn't in use and has
+ * at least minlen blocks free.
+ */
+static int
+_xfs_filestream_pick_ag(
+ xfs_mount_t *mp,
+ xfs_agnumber_t startag,
+ xfs_agnumber_t *agp,
+ int flags,
+ xfs_extlen_t minlen)
+{
+ int err, trylock, nscan;
+ xfs_extlen_t delta, longest, need, free, minfree, maxfree = 0;
+ xfs_agnumber_t ag, max_ag = NULLAGNUMBER;
+ struct xfs_perag *pag;
+
+ /* 2% of an AG's blocks must be free for it to be chosen. */
+ minfree = mp->m_sb.sb_agblocks / 50;
+
+ ag = startag;
+ *agp = NULLAGNUMBER;
+
+ /* For the first pass, don't sleep trying to init the per-AG. */
+ trylock = XFS_ALLOC_FLAG_TRYLOCK;
+
+ for (nscan = 0; 1; nscan++) {
+
+ TRACE_AG_SCAN(mp, ag, xfs_filestream_peek_ag(mp, ag));
+
+ pag = mp->m_perag + ag;
+
+ if (!pag->pagf_init) {
+ err = xfs_alloc_pagf_init(mp, NULL, ag, trylock);
+ if (err && !trylock)
+ return err;
+ }
+
+ /* Might fail sometimes during the 1st pass with trylock set. */
+ if (!pag->pagf_init)
+ goto next_ag;
+
+ /* Keep track of the AG with the most free blocks. */
+ if (pag->pagf_freeblks > maxfree) {
+ maxfree = pag->pagf_freeblks;
+ max_ag = ag;
+ }
+
+ /*
+ * The AG reference count does two things: it enforces mutual
+ * exclusion when examining the suitability of an AG in this
+ * loop, and it guards against two filestreams being established
+ * in the same AG as each other.
+ */
+ if (xfs_filestream_get_ag(mp, ag) > 1) {
+ xfs_filestream_put_ag(mp, ag);
+ goto next_ag;
+ }
+
+ need = XFS_MIN_FREELIST_PAG(pag, mp);
+ delta = need > pag->pagf_flcount ? need - pag->pagf_flcount : 0;
+ longest = (pag->pagf_longest > delta) ?
+ (pag->pagf_longest - delta) :
+ (pag->pagf_flcount > 0 || pag->pagf_longest > 0);
+
+ if (((minlen && longest >= minlen) ||
+ (!minlen && pag->pagf_freeblks >= minfree)) &&
+ (!pag->pagf_metadata || !(flags & XFS_PICK_USERDATA) ||
+ (flags & XFS_PICK_LOWSPACE))) {
+
+ /* Break out, retaining the reference on the AG. */
+ free = pag->pagf_freeblks;
+ *agp = ag;
+ break;
+ }
+
+ /* Drop the reference on this AG, it's not usable. */
+ xfs_filestream_put_ag(mp, ag);
+next_ag:
+ /* Move to the next AG, wrapping to AG 0 if necessary. */
+ if (++ag >= mp->m_sb.sb_agcount)
+ ag = 0;
+
+ /* If a full pass of the AGs hasn't been done yet, continue. */
+ if (ag != startag)
+ continue;
+
+ /* Allow sleeping in xfs_alloc_pagf_init() on the 2nd pass. */
+ if (trylock != 0) {
+ trylock = 0;
+ continue;
+ }
+
+ /* Finally, if lowspace wasn't set, set it for the 3rd pass. */
+ if (!(flags & XFS_PICK_LOWSPACE)) {
+ flags |= XFS_PICK_LOWSPACE;
+ continue;
+ }
+
+ /*
+ * Take the AG with the most free space, regardless of whether
+ * it's already in use by another filestream.
+ */
+ if (max_ag != NULLAGNUMBER) {
+ xfs_filestream_get_ag(mp, max_ag);
+ TRACE_AG_PICK1(mp, max_ag, maxfree);
+ free = maxfree;
+ *agp = max_ag;
+ break;
+ }
+
+ /* take AG 0 if none matched */
+ TRACE_AG_PICK1(mp, max_ag, maxfree);
+ *agp = 0;
+ return 0;
+ }
+
+ TRACE_AG_PICK2(mp, startag, *agp, xfs_filestream_peek_ag(mp, *agp),
+ free, nscan, flags);
+
+ return 0;
+}
+
+/*
+ * Set the allocation group number for a file or a directory, updating inode
+ * references and per-AG references as appropriate. Must be called with the
+ * m_peraglock held in read mode.
+ */
+static int
+_xfs_filestream_update_ag(
+ xfs_inode_t *ip,
+ xfs_inode_t *pip,
+ xfs_agnumber_t ag)
+{
+ int err = 0;
+ xfs_mount_t *mp;
+ xfs_mru_cache_t *cache;
+ fstrm_item_t *item;
+ xfs_agnumber_t old_ag;
+ xfs_inode_t *old_pip;
+
+ /*
+ * Either ip is a regular file and pip is a directory, or ip is a
+ * directory and pip is NULL.
+ */
+ ASSERT(ip && (((ip->i_d.di_mode & S_IFREG) && pip &&
+ (pip->i_d.di_mode & S_IFDIR)) ||
+ ((ip->i_d.di_mode & S_IFDIR) && !pip)));
+
+ mp = ip->i_mount;
+ cache = mp->m_filestream;
+
+ item = xfs_mru_cache_lookup(cache, ip->i_ino);
+ if (item) {
+ ASSERT(item->ip == ip);
+ old_ag = item->ag;
+ item->ag = ag;
+ old_pip = item->pip;
+ item->pip = pip;
+ xfs_mru_cache_done(cache);
+
+ /*
+ * If the AG has changed, drop the old ref and take a new one,
+ * effectively transferring the reference from old to new AG.
+ */
+ if (ag != old_ag) {
+ xfs_filestream_put_ag(mp, old_ag);
+ xfs_filestream_get_ag(mp, ag);
+ }
+
+ /*
+ * If ip is a file and its pip has changed, drop the old ref and
+ * take a new one.
+ */
+ if (pip && pip != old_pip) {
+ IRELE(old_pip);
+ IHOLD(pip);
+ }
+
+ TRACE_UPDATE(mp, ip, old_ag, xfs_filestream_peek_ag(mp, old_ag),
+ ag, xfs_filestream_peek_ag(mp, ag));
+ return 0;
+ }
+
+ item = kmem_zone_zalloc(item_zone, KM_MAYFAIL);
+ if (!item)
+ return ENOMEM;
+
+ item->ag = ag;
+ item->ip = ip;
+ item->pip = pip;
+
+ err = xfs_mru_cache_insert(cache, ip->i_ino, item);
+ if (err) {
+ kmem_zone_free(item_zone, item);
+ return err;
+ }
+
+ /* Take a reference on the AG. */
+ xfs_filestream_get_ag(mp, ag);
+
+ /*
+ * Take a reference on the inode itself regardless of whether it's a
+ * regular file or a directory.
+ */
+ IHOLD(ip);
+
+ /*
+ * In the case of a regular file, take a reference on the parent inode
+ * as well to ensure it remains in-core.
+ */
+ if (pip)
+ IHOLD(pip);
+
+ TRACE_UPDATE(mp, ip, ag, xfs_filestream_peek_ag(mp, ag),
+ ag, xfs_filestream_peek_ag(mp, ag));
+
+ return 0;
+}
+
+/* xfs_fstrm_free_func(): callback for freeing cached stream items. */
+void
+xfs_fstrm_free_func(
+ xfs_ino_t ino,
+ fstrm_item_t *item)
+{
+ xfs_inode_t *ip = item->ip;
+ int ref;
+
+ ASSERT(ip->i_ino == ino);
+
+ xfs_iflags_clear(ip, XFS_IFILESTREAM);
+
+ /* Drop the reference taken on the AG when the item was added. */
+ ref = xfs_filestream_put_ag(ip->i_mount, item->ag);
+
+ ASSERT(ref >= 0);
+ TRACE_FREE(ip->i_mount, ip, item->pip, item->ag,
+ xfs_filestream_peek_ag(ip->i_mount, item->ag));
+
+ /*
+ * _xfs_filestream_update_ag() always takes a reference on the inode
+ * itself, whether it's a file or a directory. Release it here.
+ * This can result in the inode being freed and so we must
+ * not hold any inode locks when freeing filesstreams objects
+ * otherwise we can deadlock here.
+ */
+ IRELE(ip);
+
+ /*
+ * In the case of a regular file, _xfs_filestream_update_ag() also
+ * takes a ref on the parent inode to keep it in-core. Release that
+ * too.
+ */
+ if (item->pip)
+ IRELE(item->pip);
+
+ /* Finally, free the memory allocated for the item. */
+ kmem_zone_free(item_zone, item);
+}
+
+/*
+ * xfs_filestream_init() is called at xfs initialisation time to set up the
+ * memory zone that will be used for filestream data structure allocation.
+ */
+int
+xfs_filestream_init(void)
+{
+ item_zone = kmem_zone_init(sizeof(fstrm_item_t), "fstrm_item");
+#ifdef XFS_FILESTREAMS_TRACE
+ xfs_filestreams_trace_buf = ktrace_alloc(XFS_FSTRM_KTRACE_SIZE, KM_SLEEP);
+#endif
+ return item_zone ? 0 : -ENOMEM;
+}
+
+/*
+ * xfs_filestream_uninit() is called at xfs termination time to destroy the
+ * memory zone that was used for filestream data structure allocation.
+ */
+void
+xfs_filestream_uninit(void)
+{
+#ifdef XFS_FILESTREAMS_TRACE
+ ktrace_free(xfs_filestreams_trace_buf);
+#endif
+ kmem_zone_destroy(item_zone);
+}
+
+/*
+ * xfs_filestream_mount() is called when a file system is mounted with the
+ * filestream option. It is responsible for allocating the data structures
+ * needed to track the new file system's file streams.
+ */
+int
+xfs_filestream_mount(
+ xfs_mount_t *mp)
+{
+ int err;
+ unsigned int lifetime, grp_count;
+
+ /*
+ * The filestream timer tunable is currently fixed within the range of
+ * one second to four minutes, with five seconds being the default. The
+ * group count is somewhat arbitrary, but it'd be nice to adhere to the
+ * timer tunable to within about 10 percent. This requires at least 10
+ * groups.
+ */
+ lifetime = xfs_fstrm_centisecs * 10;
+ grp_count = 10;
+
+ err = xfs_mru_cache_create(&mp->m_filestream, lifetime, grp_count,
+ (xfs_mru_cache_free_func_t)xfs_fstrm_free_func);
+
+ return err;
+}
+
+/*
+ * xfs_filestream_unmount() is called when a file system that was mounted with
+ * the filestream option is unmounted. It drains the data structures created
+ * to track the file system's file streams and frees all the memory that was
+ * allocated.
+ */
+void
+xfs_filestream_unmount(
+ xfs_mount_t *mp)
+{
+ xfs_mru_cache_destroy(mp->m_filestream);
+}
+
+/*
+ * If the mount point's m_perag array is going to be reallocated, all
+ * outstanding cache entries must be flushed to avoid accessing reference count
+ * addresses that have been freed. The call to xfs_filestream_flush() must be
+ * made inside the block that holds the m_peraglock in write mode to do the
+ * reallocation.
+ */
+void
+xfs_filestream_flush(
+ xfs_mount_t *mp)
+{
+ /* point in time flush, so keep the reaper running */
+ xfs_mru_cache_flush(mp->m_filestream, 1);
+}
+
+/*
+ * Return the AG of the filestream the file or directory belongs to, or
+ * NULLAGNUMBER otherwise.
+ */
+xfs_agnumber_t
+xfs_filestream_lookup_ag(
+ xfs_inode_t *ip)
+{
+ xfs_mru_cache_t *cache;
+ fstrm_item_t *item;
+ xfs_agnumber_t ag;
+ int ref;
+
+ if (!(ip->i_d.di_mode & (S_IFREG | S_IFDIR))) {
+ ASSERT(0);
+ return NULLAGNUMBER;
+ }
+
+ cache = ip->i_mount->m_filestream;
+ item = xfs_mru_cache_lookup(cache, ip->i_ino);
+ if (!item) {
+ TRACE_LOOKUP(ip->i_mount, ip, NULL, NULLAGNUMBER, 0);
+ return NULLAGNUMBER;
+ }
+
+ ASSERT(ip == item->ip);
+ ag = item->ag;
+ ref = xfs_filestream_peek_ag(ip->i_mount, ag);
+ xfs_mru_cache_done(cache);
+
+ TRACE_LOOKUP(ip->i_mount, ip, item->pip, ag, ref);
+ return ag;
+}
+
+/*
+ * xfs_filestream_associate() should only be called to associate a regular file
+ * with its parent directory. Calling it with a child directory isn't
+ * appropriate because filestreams don't apply to entire directory hierarchies.
+ * Creating a file in a child directory of an existing filestream directory
+ * starts a new filestream with its own allocation group association.
+ *
+ * Returns < 0 on error, 0 if successful association occurred, > 0 if
+ * we failed to get an association because of locking issues.
+ */
+int
+xfs_filestream_associate(
+ xfs_inode_t *pip,
+ xfs_inode_t *ip)
+{
+ xfs_mount_t *mp;
+ xfs_mru_cache_t *cache;
+ fstrm_item_t *item;
+ xfs_agnumber_t ag, rotorstep, startag;
+ int err = 0;
+
+ ASSERT(pip->i_d.di_mode & S_IFDIR);
+ ASSERT(ip->i_d.di_mode & S_IFREG);
+ if (!(pip->i_d.di_mode & S_IFDIR) || !(ip->i_d.di_mode & S_IFREG))
+ return -EINVAL;
+
+ mp = pip->i_mount;
+ cache = mp->m_filestream;
+ down_read(&mp->m_peraglock);
+
+ /*
+ * We have a problem, Houston.
+ *
+ * Taking the iolock here violates inode locking order - we already
+ * hold the ilock. Hence if we block getting this lock we may never
+ * wake. Unfortunately, that means if we can't get the lock, we're
+ * screwed in terms of getting a stream association - we can't spin
+ * waiting for the lock because someone else is waiting on the lock we
+ * hold and we cannot drop that as we are in a transaction here.
+ *
+ * Lucky for us, this inversion is rarely a problem because it's a
+ * directory inode that we are trying to lock here and that means the
+ * only place that matters is xfs_sync_inodes() and SYNC_DELWRI is
+ * used. i.e. freeze, remount-ro, quotasync or unmount.
+ *
+ * So, if we can't get the iolock without sleeping then just give up
+ */
+ if (!xfs_ilock_nowait(pip, XFS_IOLOCK_EXCL)) {
+ up_read(&mp->m_peraglock);
+ return 1;
+ }
+
+ /* If the parent directory is already in the cache, use its AG. */
+ item = xfs_mru_cache_lookup(cache, pip->i_ino);
+ if (item) {
+ ASSERT(item->ip == pip);
+ ag = item->ag;
+ xfs_mru_cache_done(cache);
+
+ TRACE_LOOKUP(mp, pip, pip, ag, xfs_filestream_peek_ag(mp, ag));
+ err = _xfs_filestream_update_ag(ip, pip, ag);
+
+ goto exit;
+ }
+
+ /*
+ * Set the starting AG using the rotor for inode32, otherwise
+ * use the directory inode's AG.
+ */
+ if (mp->m_flags & XFS_MOUNT_32BITINODES) {
+ rotorstep = xfs_rotorstep;
+ startag = (mp->m_agfrotor / rotorstep) % mp->m_sb.sb_agcount;
+ mp->m_agfrotor = (mp->m_agfrotor + 1) %
+ (mp->m_sb.sb_agcount * rotorstep);
+ } else
+ startag = XFS_INO_TO_AGNO(mp, pip->i_ino);
+
+ /* Pick a new AG for the parent inode starting at startag. */
+ err = _xfs_filestream_pick_ag(mp, startag, &ag, 0, 0);
+ if (err || ag == NULLAGNUMBER)
+ goto exit_did_pick;
+
+ /* Associate the parent inode with the AG. */
+ err = _xfs_filestream_update_ag(pip, NULL, ag);
+ if (err)
+ goto exit_did_pick;
+
+ /* Associate the file inode with the AG. */
+ err = _xfs_filestream_update_ag(ip, pip, ag);
+ if (err)
+ goto exit_did_pick;
+
+ TRACE_ASSOCIATE(mp, ip, pip, ag, xfs_filestream_peek_ag(mp, ag));
+
+exit_did_pick:
+ /*
+ * If _xfs_filestream_pick_ag() returned a valid AG, remove the
+ * reference it took on it, since the file and directory will have taken
+ * their own now if they were successfully cached.
+ */
+ if (ag != NULLAGNUMBER)
+ xfs_filestream_put_ag(mp, ag);
+
+exit:
+ xfs_iunlock(pip, XFS_IOLOCK_EXCL);
+ up_read(&mp->m_peraglock);
+ return -err;
+}
+
+/*
+ * Pick a new allocation group for the current file and its file stream. This
+ * function is called by xfs_bmap_filestreams() with the mount point's per-ag
+ * lock held.
+ */
+int
+xfs_filestream_new_ag(
+ xfs_bmalloca_t *ap,
+ xfs_agnumber_t *agp)
+{
+ int flags, err;
+ xfs_inode_t *ip, *pip = NULL;
+ xfs_mount_t *mp;
+ xfs_mru_cache_t *cache;
+ xfs_extlen_t minlen;
+ fstrm_item_t *dir, *file;
+ xfs_agnumber_t ag = NULLAGNUMBER;
+
+ ip = ap->ip;
+ mp = ip->i_mount;
+ cache = mp->m_filestream;
+ minlen = ap->alen;
+ *agp = NULLAGNUMBER;
+
+ /*
+ * Look for the file in the cache, removing it if it's found. Doing
+ * this allows it to be held across the dir lookup that follows.
+ */
+ file = xfs_mru_cache_remove(cache, ip->i_ino);
+ if (file) {
+ ASSERT(ip == file->ip);
+
+ /* Save the file's parent inode and old AG number for later. */
+ pip = file->pip;
+ ag = file->ag;
+
+ /* Look for the file's directory in the cache. */
+ dir = xfs_mru_cache_lookup(cache, pip->i_ino);
+ if (dir) {
+ ASSERT(pip == dir->ip);
+
+ /*
+ * If the directory has already moved on to a new AG,
+ * use that AG as the new AG for the file. Don't
+ * forget to twiddle the AG refcounts to match the
+ * movement.
+ */
+ if (dir->ag != file->ag) {
+ xfs_filestream_put_ag(mp, file->ag);
+ xfs_filestream_get_ag(mp, dir->ag);
+ *agp = file->ag = dir->ag;
+ }
+
+ xfs_mru_cache_done(cache);
+ }
+
+ /*
+ * Put the file back in the cache. If this fails, the free
+ * function needs to be called to tidy up in the same way as if
+ * the item had simply expired from the cache.
+ */
+ err = xfs_mru_cache_insert(cache, ip->i_ino, file);
+ if (err) {
+ xfs_fstrm_free_func(ip->i_ino, file);
+ return err;
+ }
+
+ /*
+ * If the file's AG was moved to the directory's new AG, there's
+ * nothing more to be done.
+ */
+ if (*agp != NULLAGNUMBER) {
+ TRACE_MOVEAG(mp, ip, pip,
+ ag, xfs_filestream_peek_ag(mp, ag),
+ *agp, xfs_filestream_peek_ag(mp, *agp));
+ return 0;
+ }
+ }
+
+ /*
+ * If the file's parent directory is known, take its iolock in exclusive
+ * mode to prevent two sibling files from racing each other to migrate
+ * themselves and their parent to different AGs.
+ */
+ if (pip)
+ xfs_ilock(pip, XFS_IOLOCK_EXCL);
+
+ /*
+ * A new AG needs to be found for the file. If the file's parent
+ * directory is also known, it will be moved to the new AG as well to
+ * ensure that files created inside it in future use the new AG.
+ */
+ ag = (ag == NULLAGNUMBER) ? 0 : (ag + 1) % mp->m_sb.sb_agcount;
+ flags = (ap->userdata ? XFS_PICK_USERDATA : 0) |
+ (ap->low ? XFS_PICK_LOWSPACE : 0);
+
+ err = _xfs_filestream_pick_ag(mp, ag, agp, flags, minlen);
+ if (err || *agp == NULLAGNUMBER)
+ goto exit;
+
+ /*
+ * If the file wasn't found in the file cache, then its parent directory
+ * inode isn't known. For this to have happened, the file must either
+ * be pre-existing, or it was created long enough ago that its cache
+ * entry has expired. This isn't the sort of usage that the filestreams
+ * allocator is trying to optimise, so there's no point trying to track
+ * its new AG somehow in the filestream data structures.
+ */
+ if (!pip) {
+ TRACE_ORPHAN(mp, ip, *agp);
+ goto exit;
+ }
+
+ /* Associate the parent inode with the AG. */
+ err = _xfs_filestream_update_ag(pip, NULL, *agp);
+ if (err)
+ goto exit;
+
+ /* Associate the file inode with the AG. */
+ err = _xfs_filestream_update_ag(ip, pip, *agp);
+ if (err)
+ goto exit;
+
+ TRACE_MOVEAG(mp, ip, pip, NULLAGNUMBER, 0,
+ *agp, xfs_filestream_peek_ag(mp, *agp));
+
+exit:
+ /*
+ * If _xfs_filestream_pick_ag() returned a valid AG, remove the
+ * reference it took on it, since the file and directory will have taken
+ * their own now if they were successfully cached.
+ */
+ if (*agp != NULLAGNUMBER)
+ xfs_filestream_put_ag(mp, *agp);
+ else
+ *agp = 0;
+
+ if (pip)
+ xfs_iunlock(pip, XFS_IOLOCK_EXCL);
+
+ return err;
+}
+
+/*
+ * Remove an association between an inode and a filestream object.
+ * Typically this is done on last close of an unlinked file.
+ */
+void
+xfs_filestream_deassociate(
+ xfs_inode_t *ip)
+{
+ xfs_mru_cache_t *cache = ip->i_mount->m_filestream;
+
+ xfs_mru_cache_delete(cache, ip->i_ino);
+}