diff options
Diffstat (limited to 'fs/xfs/xfs_filestream.c')
| -rw-r--r-- | fs/xfs/xfs_filestream.c | 818 |
1 files changed, 818 insertions, 0 deletions
diff --git a/fs/xfs/xfs_filestream.c b/fs/xfs/xfs_filestream.c new file mode 100644 index 00000000..9b715dce --- /dev/null +++ b/fs/xfs/xfs_filestream.c @@ -0,0 +1,818 @@ +/* + * 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_dinode.h" +#include "xfs_inode.h" +#include "xfs_ag.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" +#include "xfs_trace.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, __func__, __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; + +/* + * Allocation group filestream associations are tracked with per-ag atomic + * counters. These counters allow _xfs_filestream_pick_ag() to tell whether a + * particular AG already has active filestreams associated with it. The mount + * point's m_peraglock is used to protect these counters from per-ag array + * re-allocation during a growfs operation. When xfs_growfs_data_private() is + * about to reallocate the array, it calls xfs_filestream_flush() with the + * m_peraglock held in write mode. + * + * Since xfs_mru_cache_flush() guarantees that all the free functions for all + * the cache elements have finished executing before it returns, it's safe for + * the free functions to use the atomic counters without m_peraglock protection. + * This allows the implementation of xfs_fstrm_free_func() to be agnostic about + * whether it was called with the m_peraglock held in read mode, write mode or + * not held at all. The race condition this addresses is the following: + * + * - The work queue scheduler fires and pulls a filestream directory cache + * element off the LRU end of the cache for deletion, then gets pre-empted. + * - A growfs operation grabs the m_peraglock in write mode, flushes all the + * remaining items from the cache and reallocates the mount point's per-ag + * array, resetting all the counters to zero. + * - The work queue thread resumes and calls the free function for the element + * it started cleaning up earlier. In the process it decrements the + * filestreams counter for an AG that now has no references. + * + * With a shrinkfs feature, the above scenario could panic the system. + * + * All other uses of the following macros should be protected by either the + * m_peraglock held in read mode, or the cache's internal locking exposed by the + * interval between a call to xfs_mru_cache_lookup() and a call to + * xfs_mru_cache_done(). In addition, the m_peraglock must be held in read mode + * when new elements are added to the cache. + * + * Combined, these locking rules ensure that no associations will ever exist in + * the cache that reference per-ag array elements that have since been + * reallocated. + */ +static int +xfs_filestream_peek_ag( + xfs_mount_t *mp, + xfs_agnumber_t agno) +{ + struct xfs_perag *pag; + int ret; + + pag = xfs_perag_get(mp, agno); + ret = atomic_read(&pag->pagf_fstrms); + xfs_perag_put(pag); + return ret; +} + +static int +xfs_filestream_get_ag( + xfs_mount_t *mp, + xfs_agnumber_t agno) +{ + struct xfs_perag *pag; + int ret; + + pag = xfs_perag_get(mp, agno); + ret = atomic_inc_return(&pag->pagf_fstrms); + xfs_perag_put(pag); + return ret; +} + +static void +xfs_filestream_put_ag( + xfs_mount_t *mp, + xfs_agnumber_t agno) +{ + struct xfs_perag *pag; + + pag = xfs_perag_get(mp, agno); + atomic_dec(&pag->pagf_fstrms); + xfs_perag_put(pag); +} + +/* + * 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 streams, max_streams; + int err, trylock, nscan; + xfs_extlen_t longest, 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++) { + pag = xfs_perag_get(mp, ag); + TRACE_AG_SCAN(mp, ag, atomic_read(&pag->pagf_fstrms)); + + if (!pag->pagf_init) { + err = xfs_alloc_pagf_init(mp, NULL, ag, trylock); + if (err && !trylock) { + xfs_perag_put(pag); + 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_streams = atomic_read(&pag->pagf_fstrms); + 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; + } + + longest = xfs_alloc_longest_free_extent(mp, pag); + 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; + streams = atomic_read(&pag->pagf_fstrms); + xfs_perag_put(pag); + *agp = ag; + break; + } + + /* Drop the reference on this AG, it's not usable. */ + xfs_filestream_put_ag(mp, ag); +next_ag: + xfs_perag_put(pag); + /* 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); + streams = max_streams; + 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, streams, 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. + */ +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. */ +STATIC void +xfs_fstrm_free_func( + unsigned long ino, + void *data) +{ + fstrm_item_t *item = (fstrm_item_t *)data; + xfs_inode_t *ip = item->ip; + + ASSERT(ip->i_ino == ino); + + xfs_iflags_clear(ip, XFS_IFILESTREAM); + + /* Drop the reference taken on the AG when the item was added. */ + xfs_filestream_put_ag(ip->i_mount, item->ag); + + 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"); + if (!item_zone) + return -ENOMEM; + + return 0; +} + +/* + * 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) +{ + 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_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); +} + +/* + * 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; + + /* + * 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 not a problem because it's a + * directory inode that we are trying to lock here. + * + * So, if we can't get the iolock without sleeping then just give up + */ + if (!xfs_ilock_nowait(pip, XFS_IOLOCK_EXCL)) + 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); + 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); +} |