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gerrit-public.fairphone.software / kernel / msm-4.19 / a848e3b67c07ed79374bd0f9b82f9ce45a419643 / . / fs / xfs / xfs_mount.c
blob: f5aa3ef855fbb5e793d4d7f8eeecb507a5dc99fa [file] [log] [blame]
/*
* 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_types.h"
#include "xfs_bit.h"
#include "xfs_log.h"
#include "xfs_inum.h"
#include "xfs_trans.h"
#include "xfs_sb.h"
#include "xfs_ag.h"
#include "xfs_dir2.h"
#include "xfs_dmapi.h"
#include "xfs_mount.h"
#include "xfs_bmap_btree.h"
#include "xfs_alloc_btree.h"
#include "xfs_ialloc_btree.h"
#include "xfs_dir2_sf.h"
#include "xfs_attr_sf.h"
#include "xfs_dinode.h"
#include "xfs_inode.h"
#include "xfs_btree.h"
#include "xfs_ialloc.h"
#include "xfs_alloc.h"
#include "xfs_rtalloc.h"
#include "xfs_bmap.h"
#include "xfs_error.h"
#include "xfs_rw.h"
#include "xfs_quota.h"
#include "xfs_fsops.h"
STATIC void xfs_mount_log_sbunit(xfs_mount_t *, __int64_t);
STATIC int xfs_uuid_mount(xfs_mount_t *);
STATIC void xfs_uuid_unmount(xfs_mount_t *mp);
STATIC void xfs_unmountfs_wait(xfs_mount_t *);
#ifdef HAVE_PERCPU_SB
STATIC void xfs_icsb_destroy_counters(xfs_mount_t *);
STATIC void xfs_icsb_balance_counter(xfs_mount_t *, xfs_sb_field_t,
int, int);
STATIC void xfs_icsb_sync_counters(xfs_mount_t *);
STATIC int xfs_icsb_modify_counters(xfs_mount_t *, xfs_sb_field_t,
int64_t, int);
STATIC int xfs_icsb_disable_counter(xfs_mount_t *, xfs_sb_field_t);
#else
#define xfs_icsb_destroy_counters(mp) do { } while (0)
#define xfs_icsb_balance_counter(mp, a, b, c) do { } while (0)
#define xfs_icsb_sync_counters(mp) do { } while (0)
#define xfs_icsb_modify_counters(mp, a, b, c) do { } while (0)
#endif
static const struct {
short offset;
short type; /* 0 = integer
* 1 = binary / string (no translation)
*/
} xfs_sb_info[] = {
{ offsetof(xfs_sb_t, sb_magicnum), 0 },
{ offsetof(xfs_sb_t, sb_blocksize), 0 },
{ offsetof(xfs_sb_t, sb_dblocks), 0 },
{ offsetof(xfs_sb_t, sb_rblocks), 0 },
{ offsetof(xfs_sb_t, sb_rextents), 0 },
{ offsetof(xfs_sb_t, sb_uuid), 1 },
{ offsetof(xfs_sb_t, sb_logstart), 0 },
{ offsetof(xfs_sb_t, sb_rootino), 0 },
{ offsetof(xfs_sb_t, sb_rbmino), 0 },
{ offsetof(xfs_sb_t, sb_rsumino), 0 },
{ offsetof(xfs_sb_t, sb_rextsize), 0 },
{ offsetof(xfs_sb_t, sb_agblocks), 0 },
{ offsetof(xfs_sb_t, sb_agcount), 0 },
{ offsetof(xfs_sb_t, sb_rbmblocks), 0 },
{ offsetof(xfs_sb_t, sb_logblocks), 0 },
{ offsetof(xfs_sb_t, sb_versionnum), 0 },
{ offsetof(xfs_sb_t, sb_sectsize), 0 },
{ offsetof(xfs_sb_t, sb_inodesize), 0 },
{ offsetof(xfs_sb_t, sb_inopblock), 0 },
{ offsetof(xfs_sb_t, sb_fname[0]), 1 },
{ offsetof(xfs_sb_t, sb_blocklog), 0 },
{ offsetof(xfs_sb_t, sb_sectlog), 0 },
{ offsetof(xfs_sb_t, sb_inodelog), 0 },
{ offsetof(xfs_sb_t, sb_inopblog), 0 },
{ offsetof(xfs_sb_t, sb_agblklog), 0 },
{ offsetof(xfs_sb_t, sb_rextslog), 0 },
{ offsetof(xfs_sb_t, sb_inprogress), 0 },
{ offsetof(xfs_sb_t, sb_imax_pct), 0 },
{ offsetof(xfs_sb_t, sb_icount), 0 },
{ offsetof(xfs_sb_t, sb_ifree), 0 },
{ offsetof(xfs_sb_t, sb_fdblocks), 0 },
{ offsetof(xfs_sb_t, sb_frextents), 0 },
{ offsetof(xfs_sb_t, sb_uquotino), 0 },
{ offsetof(xfs_sb_t, sb_gquotino), 0 },
{ offsetof(xfs_sb_t, sb_qflags), 0 },
{ offsetof(xfs_sb_t, sb_flags), 0 },
{ offsetof(xfs_sb_t, sb_shared_vn), 0 },
{ offsetof(xfs_sb_t, sb_inoalignmt), 0 },
{ offsetof(xfs_sb_t, sb_unit), 0 },
{ offsetof(xfs_sb_t, sb_width), 0 },
{ offsetof(xfs_sb_t, sb_dirblklog), 0 },
{ offsetof(xfs_sb_t, sb_logsectlog), 0 },
{ offsetof(xfs_sb_t, sb_logsectsize),0 },
{ offsetof(xfs_sb_t, sb_logsunit), 0 },
{ offsetof(xfs_sb_t, sb_features2), 0 },
{ sizeof(xfs_sb_t), 0 }
};
/*
* Return a pointer to an initialized xfs_mount structure.
*/
xfs_mount_t *
xfs_mount_init(void)
{
xfs_mount_t *mp;
mp = kmem_zalloc(sizeof(xfs_mount_t), KM_SLEEP);
if (xfs_icsb_init_counters(mp)) {
mp->m_flags |= XFS_MOUNT_NO_PERCPU_SB;
}
AIL_LOCKINIT(&mp->m_ail_lock, "xfs_ail");
spinlock_init(&mp->m_sb_lock, "xfs_sb");
mutex_init(&mp->m_ilock);
initnsema(&mp->m_growlock, 1, "xfs_grow");
/*
* Initialize the AIL.
*/
xfs_trans_ail_init(mp);
atomic_set(&mp->m_active_trans, 0);
return mp;
}
/*
* Free up the resources associated with a mount structure. Assume that
* the structure was initially zeroed, so we can tell which fields got
* initialized.
*/
void
xfs_mount_free(
xfs_mount_t *mp,
int remove_bhv)
{
if (mp->m_ihash)
xfs_ihash_free(mp);
if (mp->m_chash)
xfs_chash_free(mp);
if (mp->m_perag) {
int agno;
for (agno = 0; agno < mp->m_maxagi; agno++)
if (mp->m_perag[agno].pagb_list)
kmem_free(mp->m_perag[agno].pagb_list,
sizeof(xfs_perag_busy_t) *
XFS_PAGB_NUM_SLOTS);
kmem_free(mp->m_perag,
sizeof(xfs_perag_t) * mp->m_sb.sb_agcount);
}
AIL_LOCK_DESTROY(&mp->m_ail_lock);
spinlock_destroy(&mp->m_sb_lock);
mutex_destroy(&mp->m_ilock);
freesema(&mp->m_growlock);
if (mp->m_quotainfo)
XFS_QM_DONE(mp);
if (mp->m_fsname != NULL)
kmem_free(mp->m_fsname, mp->m_fsname_len);
if (mp->m_rtname != NULL)
kmem_free(mp->m_rtname, strlen(mp->m_rtname) + 1);
if (mp->m_logname != NULL)
kmem_free(mp->m_logname, strlen(mp->m_logname) + 1);
if (remove_bhv) {
struct bhv_vfs *vfsp = XFS_MTOVFS(mp);
bhv_remove_all_vfsops(vfsp, 0);
VFS_REMOVEBHV(vfsp, &mp->m_bhv);
}
xfs_icsb_destroy_counters(mp);
kmem_free(mp, sizeof(xfs_mount_t));
}
/*
* Check the validity of the SB found.
*/
STATIC int
xfs_mount_validate_sb(
xfs_mount_t *mp,
xfs_sb_t *sbp,
int flags)
{
/*
* If the log device and data device have the
* same device number, the log is internal.
* Consequently, the sb_logstart should be non-zero. If
* we have a zero sb_logstart in this case, we may be trying to mount
* a volume filesystem in a non-volume manner.
*/
if (sbp->sb_magicnum != XFS_SB_MAGIC) {
xfs_fs_mount_cmn_err(flags, "bad magic number");
return XFS_ERROR(EWRONGFS);
}
if (!XFS_SB_GOOD_VERSION(sbp)) {
xfs_fs_mount_cmn_err(flags, "bad version");
return XFS_ERROR(EWRONGFS);
}
if (unlikely(
sbp->sb_logstart == 0 && mp->m_logdev_targp == mp->m_ddev_targp)) {
xfs_fs_mount_cmn_err(flags,
"filesystem is marked as having an external log; "
"specify logdev on the\nmount command line.");
return XFS_ERROR(EINVAL);
}
if (unlikely(
sbp->sb_logstart != 0 && mp->m_logdev_targp != mp->m_ddev_targp)) {
xfs_fs_mount_cmn_err(flags,
"filesystem is marked as having an internal log; "
"do not specify logdev on\nthe mount command line.");
return XFS_ERROR(EINVAL);
}
/*
* More sanity checking. These were stolen directly from
* xfs_repair.
*/
if (unlikely(
sbp->sb_agcount <= 0 ||
sbp->sb_sectsize < XFS_MIN_SECTORSIZE ||
sbp->sb_sectsize > XFS_MAX_SECTORSIZE ||
sbp->sb_sectlog < XFS_MIN_SECTORSIZE_LOG ||
sbp->sb_sectlog > XFS_MAX_SECTORSIZE_LOG ||
sbp->sb_blocksize < XFS_MIN_BLOCKSIZE ||
sbp->sb_blocksize > XFS_MAX_BLOCKSIZE ||
sbp->sb_blocklog < XFS_MIN_BLOCKSIZE_LOG ||
sbp->sb_blocklog > XFS_MAX_BLOCKSIZE_LOG ||
sbp->sb_inodesize < XFS_DINODE_MIN_SIZE ||
sbp->sb_inodesize > XFS_DINODE_MAX_SIZE ||
sbp->sb_inodelog < XFS_DINODE_MIN_LOG ||
sbp->sb_inodelog > XFS_DINODE_MAX_LOG ||
(sbp->sb_blocklog - sbp->sb_inodelog != sbp->sb_inopblog) ||
(sbp->sb_rextsize * sbp->sb_blocksize > XFS_MAX_RTEXTSIZE) ||
(sbp->sb_rextsize * sbp->sb_blocksize < XFS_MIN_RTEXTSIZE) ||
(sbp->sb_imax_pct > 100 /* zero sb_imax_pct is valid */))) {
xfs_fs_mount_cmn_err(flags, "SB sanity check 1 failed");
return XFS_ERROR(EFSCORRUPTED);
}
/*
* Sanity check AG count, size fields against data size field
*/
if (unlikely(
sbp->sb_dblocks == 0 ||
sbp->sb_dblocks >
(xfs_drfsbno_t)sbp->sb_agcount * sbp->sb_agblocks ||
sbp->sb_dblocks < (xfs_drfsbno_t)(sbp->sb_agcount - 1) *
sbp->sb_agblocks + XFS_MIN_AG_BLOCKS)) {
xfs_fs_mount_cmn_err(flags, "SB sanity check 2 failed");
return XFS_ERROR(EFSCORRUPTED);
}
ASSERT(PAGE_SHIFT >= sbp->sb_blocklog);
ASSERT(sbp->sb_blocklog >= BBSHIFT);
#if XFS_BIG_BLKNOS /* Limited by ULONG_MAX of page cache index */
if (unlikely(
(sbp->sb_dblocks >> (PAGE_SHIFT - sbp->sb_blocklog)) > ULONG_MAX ||
(sbp->sb_rblocks >> (PAGE_SHIFT - sbp->sb_blocklog)) > ULONG_MAX)) {
#else /* Limited by UINT_MAX of sectors */
if (unlikely(
(sbp->sb_dblocks << (sbp->sb_blocklog - BBSHIFT)) > UINT_MAX ||
(sbp->sb_rblocks << (sbp->sb_blocklog - BBSHIFT)) > UINT_MAX)) {
#endif
xfs_fs_mount_cmn_err(flags,
"file system too large to be mounted on this system.");
return XFS_ERROR(E2BIG);
}
if (unlikely(sbp->sb_inprogress)) {
xfs_fs_mount_cmn_err(flags, "file system busy");
return XFS_ERROR(EFSCORRUPTED);
}
/*
* Version 1 directory format has never worked on Linux.
*/
if (unlikely(!XFS_SB_VERSION_HASDIRV2(sbp))) {
xfs_fs_mount_cmn_err(flags,
"file system using version 1 directory format");
return XFS_ERROR(ENOSYS);
}
/*
* Until this is fixed only page-sized or smaller data blocks work.
*/
if (unlikely(sbp->sb_blocksize > PAGE_SIZE)) {
xfs_fs_mount_cmn_err(flags,
"file system with blocksize %d bytes",
sbp->sb_blocksize);
xfs_fs_mount_cmn_err(flags,
"only pagesize (%ld) or less will currently work.",
PAGE_SIZE);
return XFS_ERROR(ENOSYS);
}
return 0;
}
xfs_agnumber_t
xfs_initialize_perag(
bhv_vfs_t *vfs,
xfs_mount_t *mp,
xfs_agnumber_t agcount)
{
xfs_agnumber_t index, max_metadata;
xfs_perag_t *pag;
xfs_agino_t agino;
xfs_ino_t ino;
xfs_sb_t *sbp = &mp->m_sb;
xfs_ino_t max_inum = XFS_MAXINUMBER_32;
/* Check to see if the filesystem can overflow 32 bit inodes */
agino = XFS_OFFBNO_TO_AGINO(mp, sbp->sb_agblocks - 1, 0);
ino = XFS_AGINO_TO_INO(mp, agcount - 1, agino);
/* Clear the mount flag if no inode can overflow 32 bits
* on this filesystem, or if specifically requested..
*/
if ((vfs->vfs_flag & VFS_32BITINODES) && ino > max_inum) {
mp->m_flags |= XFS_MOUNT_32BITINODES;
} else {
mp->m_flags &= ~XFS_MOUNT_32BITINODES;
}
/* If we can overflow then setup the ag headers accordingly */
if (mp->m_flags & XFS_MOUNT_32BITINODES) {
/* Calculate how much should be reserved for inodes to
* meet the max inode percentage.
*/
if (mp->m_maxicount) {
__uint64_t icount;
icount = sbp->sb_dblocks * sbp->sb_imax_pct;
do_div(icount, 100);
icount += sbp->sb_agblocks - 1;
do_div(icount, sbp->sb_agblocks);
max_metadata = icount;
} else {
max_metadata = agcount;
}
for (index = 0; index < agcount; index++) {
ino = XFS_AGINO_TO_INO(mp, index, agino);
if (ino > max_inum) {
index++;
break;
}
/* This ag is preferred for inodes */
pag = &mp->m_perag[index];
pag->pagi_inodeok = 1;
if (index < max_metadata)
pag->pagf_metadata = 1;
}
} else {
/* Setup default behavior for smaller filesystems */
for (index = 0; index < agcount; index++) {
pag = &mp->m_perag[index];
pag->pagi_inodeok = 1;
}
}
return index;
}
/*
* xfs_xlatesb
*
* data - on disk version of sb
* sb - a superblock
* dir - conversion direction: <0 - convert sb to buf
* >0 - convert buf to sb
* fields - which fields to copy (bitmask)
*/
void
xfs_xlatesb(
void *data,
xfs_sb_t *sb,
int dir,
__int64_t fields)
{
xfs_caddr_t buf_ptr;
xfs_caddr_t mem_ptr;
xfs_sb_field_t f;
int first;
int size;
ASSERT(dir);
ASSERT(fields);
if (!fields)
return;
buf_ptr = (xfs_caddr_t)data;
mem_ptr = (xfs_caddr_t)sb;
while (fields) {
f = (xfs_sb_field_t)xfs_lowbit64((__uint64_t)fields);
first = xfs_sb_info[f].offset;
size = xfs_sb_info[f + 1].offset - first;
ASSERT(xfs_sb_info[f].type == 0 || xfs_sb_info[f].type == 1);
if (size == 1 || xfs_sb_info[f].type == 1) {
if (dir > 0) {
memcpy(mem_ptr + first, buf_ptr + first, size);
} else {
memcpy(buf_ptr + first, mem_ptr + first, size);
}
} else {
switch (size) {
case 2:
INT_XLATE(*(__uint16_t*)(buf_ptr+first),
*(__uint16_t*)(mem_ptr+first),
dir, ARCH_CONVERT);
break;
case 4:
INT_XLATE(*(__uint32_t*)(buf_ptr+first),
*(__uint32_t*)(mem_ptr+first),
dir, ARCH_CONVERT);
break;
case 8:
INT_XLATE(*(__uint64_t*)(buf_ptr+first),
*(__uint64_t*)(mem_ptr+first), dir, ARCH_CONVERT);
break;
default:
ASSERT(0);
}
}
fields &= ~(1LL << f);
}
}
/*
* xfs_readsb
*
* Does the initial read of the superblock.
*/
int
xfs_readsb(xfs_mount_t *mp, int flags)
{
unsigned int sector_size;
unsigned int extra_flags;
xfs_buf_t *bp;
xfs_sb_t *sbp;
int error;
ASSERT(mp->m_sb_bp == NULL);
ASSERT(mp->m_ddev_targp != NULL);
/*
* Allocate a (locked) buffer to hold the superblock.
* This will be kept around at all times to optimize
* access to the superblock.
*/
sector_size = xfs_getsize_buftarg(mp->m_ddev_targp);
extra_flags = XFS_BUF_LOCK | XFS_BUF_MANAGE | XFS_BUF_MAPPED;
bp = xfs_buf_read_flags(mp->m_ddev_targp, XFS_SB_DADDR,
BTOBB(sector_size), extra_flags);
if (!bp || XFS_BUF_ISERROR(bp)) {
xfs_fs_mount_cmn_err(flags, "SB read failed");
error = bp ? XFS_BUF_GETERROR(bp) : ENOMEM;
goto fail;
}
ASSERT(XFS_BUF_ISBUSY(bp));
ASSERT(XFS_BUF_VALUSEMA(bp) <= 0);
/*
* Initialize the mount structure from the superblock.
* But first do some basic consistency checking.
*/
sbp = XFS_BUF_TO_SBP(bp);
xfs_xlatesb(XFS_BUF_PTR(bp), &(mp->m_sb), 1, XFS_SB_ALL_BITS);
error = xfs_mount_validate_sb(mp, &(mp->m_sb), flags);
if (error) {
xfs_fs_mount_cmn_err(flags, "SB validate failed");
goto fail;
}
/*
* We must be able to do sector-sized and sector-aligned IO.
*/
if (sector_size > mp->m_sb.sb_sectsize) {
xfs_fs_mount_cmn_err(flags,
"device supports only %u byte sectors (not %u)",
sector_size, mp->m_sb.sb_sectsize);
error = ENOSYS;
goto fail;
}
/*
* If device sector size is smaller than the superblock size,
* re-read the superblock so the buffer is correctly sized.
*/
if (sector_size < mp->m_sb.sb_sectsize) {
XFS_BUF_UNMANAGE(bp);
xfs_buf_relse(bp);
sector_size = mp->m_sb.sb_sectsize;
bp = xfs_buf_read_flags(mp->m_ddev_targp, XFS_SB_DADDR,
BTOBB(sector_size), extra_flags);
if (!bp || XFS_BUF_ISERROR(bp)) {
xfs_fs_mount_cmn_err(flags, "SB re-read failed");
error = bp ? XFS_BUF_GETERROR(bp) : ENOMEM;
goto fail;
}
ASSERT(XFS_BUF_ISBUSY(bp));
ASSERT(XFS_BUF_VALUSEMA(bp) <= 0);
}
/* Initialize per-cpu counters */
xfs_icsb_reinit_counters(mp);
mp->m_sb_bp = bp;
xfs_buf_relse(bp);
ASSERT(XFS_BUF_VALUSEMA(bp) > 0);
return 0;
fail:
if (bp) {
XFS_BUF_UNMANAGE(bp);
xfs_buf_relse(bp);
}
return error;
}
/*
* xfs_mount_common
*
* Mount initialization code establishing various mount
* fields from the superblock associated with the given
* mount structure
*/
STATIC void
xfs_mount_common(xfs_mount_t *mp, xfs_sb_t *sbp)
{
int i;
mp->m_agfrotor = mp->m_agirotor = 0;
spinlock_init(&mp->m_agirotor_lock, "m_agirotor_lock");
mp->m_maxagi = mp->m_sb.sb_agcount;
mp->m_blkbit_log = sbp->sb_blocklog + XFS_NBBYLOG;
mp->m_blkbb_log = sbp->sb_blocklog - BBSHIFT;
mp->m_sectbb_log = sbp->sb_sectlog - BBSHIFT;
mp->m_agno_log = xfs_highbit32(sbp->sb_agcount - 1) + 1;
mp->m_agino_log = sbp->sb_inopblog + sbp->sb_agblklog;
mp->m_litino = sbp->sb_inodesize -
((uint)sizeof(xfs_dinode_core_t) + (uint)sizeof(xfs_agino_t));
mp->m_blockmask = sbp->sb_blocksize - 1;
mp->m_blockwsize = sbp->sb_blocksize >> XFS_WORDLOG;
mp->m_blockwmask = mp->m_blockwsize - 1;
INIT_LIST_HEAD(&mp->m_del_inodes);
/*
* Setup for attributes, in case they get created.
* This value is for inodes getting attributes for the first time,
* the per-inode value is for old attribute values.
*/
ASSERT(sbp->sb_inodesize >= 256 && sbp->sb_inodesize <= 2048);
switch (sbp->sb_inodesize) {
case 256:
mp->m_attroffset = XFS_LITINO(mp) -
XFS_BMDR_SPACE_CALC(MINABTPTRS);
break;
case 512:
case 1024:
case 2048:
mp->m_attroffset = XFS_BMDR_SPACE_CALC(6 * MINABTPTRS);
break;
default:
ASSERT(0);
}
ASSERT(mp->m_attroffset < XFS_LITINO(mp));
for (i = 0; i < 2; i++) {
mp->m_alloc_mxr[i] = XFS_BTREE_BLOCK_MAXRECS(sbp->sb_blocksize,
xfs_alloc, i == 0);
mp->m_alloc_mnr[i] = XFS_BTREE_BLOCK_MINRECS(sbp->sb_blocksize,
xfs_alloc, i == 0);
}
for (i = 0; i < 2; i++) {
mp->m_bmap_dmxr[i] = XFS_BTREE_BLOCK_MAXRECS(sbp->sb_blocksize,
xfs_bmbt, i == 0);
mp->m_bmap_dmnr[i] = XFS_BTREE_BLOCK_MINRECS(sbp->sb_blocksize,
xfs_bmbt, i == 0);
}
for (i = 0; i < 2; i++) {
mp->m_inobt_mxr[i] = XFS_BTREE_BLOCK_MAXRECS(sbp->sb_blocksize,
xfs_inobt, i == 0);
mp->m_inobt_mnr[i] = XFS_BTREE_BLOCK_MINRECS(sbp->sb_blocksize,
xfs_inobt, i == 0);
}
mp->m_bsize = XFS_FSB_TO_BB(mp, 1);
mp->m_ialloc_inos = (int)MAX((__uint16_t)XFS_INODES_PER_CHUNK,
sbp->sb_inopblock);
mp->m_ialloc_blks = mp->m_ialloc_inos >> sbp->sb_inopblog;
}
/*
* 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(
bhv_vfs_t *vfsp,
xfs_mount_t *mp,
int mfsi_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 ret64;
__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
* of the fs blocksize turn off alignment.
*/
if ((BBTOB(mp->m_dalign) & mp->m_blockmask) ||
(BBTOB(mp->m_swidth) & mp->m_blockmask)) {
if (mp->m_flags & XFS_MOUNT_RETERR) {
cmn_err(CE_WARN,
"XFS: alignment check 1 failed");
error = XFS_ERROR(EINVAL);
goto error1;
}
mp->m_dalign = mp->m_swidth = 0;
} 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)) {
if (mp->m_flags & XFS_MOUNT_RETERR) {
error = XFS_ERROR(EINVAL);
goto error1;
}
xfs_fs_cmn_err(CE_WARN, mp,
"stripe alignment turned off: sunit(%d)/swidth(%d) incompatible with agsize(%d)",
mp->m_dalign, mp->m_swidth,
sbp->sb_agblocks);
mp->m_dalign = 0;
mp->m_swidth = 0;
} else if (mp->m_dalign) {
mp->m_swidth = XFS_BB_TO_FSBT(mp, mp->m_swidth);
} else {
if (mp->m_flags & XFS_MOUNT_RETERR) {
xfs_fs_cmn_err(CE_WARN, mp,
"stripe alignment turned off: sunit(%d) less than bsize(%d)",
mp->m_dalign,
mp->m_blockmask +1);
error = XFS_ERROR(EINVAL);
goto error1;
}
mp->m_swidth = 0;
}
}
/*
* 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;
update_flags |= XFS_SB_UNIT;
}
if (sbp->sb_width != mp->m_swidth) {
sbp->sb_width = mp->m_swidth;
update_flags |= XFS_SB_WIDTH;
}
}
} 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;
}
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);
if (sbp->sb_imax_pct) {
__uint64_t icount;
/* 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;
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;
ret64 = uuid_hash64(&sbp->sb_uuid);
memcpy(&vfsp->vfs_fsid, &ret64, sizeof(ret64));
}
/*
* 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;
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;
}
/*
* Set the number of readahead buffers to use based on
* physical memory size.
*/
if (xfs_physmem <= 4096) /* <= 16MB */
mp->m_nreadaheads = XFS_RW_NREADAHEAD_16MB;
else if (xfs_physmem <= 8192) /* <= 32MB */
mp->m_nreadaheads = XFS_RW_NREADAHEAD_32MB;
else
mp->m_nreadaheads = XFS_RW_NREADAHEAD_K32;
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);
/*
* Set the inode cluster size based on the physical memory
* size. This may still be overridden by the file system
* block size if it is larger than the chosen cluster size.
*/
if (xfs_physmem <= btoc(32 * 1024 * 1024)) { /* <= 32 MB */
mp->m_inode_cluster_size = XFS_INODE_SMALL_CLUSTER_SIZE;
} else {
mp->m_inode_cluster_size = XFS_INODE_BIG_CLUSTER_SIZE;
}
/*
* Set whether we're using inode alignment.
*/
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) are an ok size.
*/
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;
}
error = xfs_read_buf(mp, mp->m_ddev_targp,
d - XFS_FSS_TO_BB(mp, 1),
XFS_FSS_TO_BB(mp, 1), 0, &bp);
if (!error) {
xfs_buf_relse(bp);
} else {
cmn_err(CE_WARN, "XFS: size check 2 failed");
if (error == ENOSPC) {
error = XFS_ERROR(E2BIG);
}
goto error1;
}
if (((mfsi_flags & XFS_MFSI_CLIENT) == 0) &&
mp->m_logdev_targp != mp->m_ddev_targp) {
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;
}
error = xfs_read_buf(mp, mp->m_logdev_targp,
d - XFS_FSB_TO_BB(mp, 1),
XFS_FSB_TO_BB(mp, 1), 0, &bp);
if (!error) {
xfs_buf_relse(bp);
} else {
cmn_err(CE_WARN, "XFS: size check 3 failed");
if (error == ENOSPC) {
error = XFS_ERROR(E2BIG);
}
goto error1;
}
}
/*
* Initialize realtime fields in the mount structure
*/
if ((error = xfs_rtmount_init(mp))) {
cmn_err(CE_WARN, "XFS: RT mount failed");
goto error1;
}
/*
* For client case we are done now
*/
if (mfsi_flags & XFS_MFSI_CLIENT) {
return 0;
}
/*
* 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);
/*
* The vfs structure needs to have a file system independent
* way of checking for the invariant file system ID. Since it
* can't look at mount structures it has a pointer to the data
* in the mount structure.
*
* File systems that don't support user level file handles (i.e.
* all of them except for XFS) will leave vfs_altfsid as NULL.
*/
vfsp->vfs_altfsid = (xfs_fsid_t *)mp->m_fixedfsid;
mp->m_dmevmask = 0; /* not persistent; set after each mount */
xfs_dir_mount(mp);
/*
* Initialize the attribute manager's entries.
*/
mp->m_attr_magicpct = (mp->m_sb.sb_blocksize * 37) / 100;
/*
* Initialize the precomputed transaction reservations values.
*/
xfs_trans_init(mp);
/*
* Allocate and initialize the inode hash table for this
* file system.
*/
xfs_ihash_init(mp);
xfs_chash_init(mp);
/*
* Allocate and initialize the per-ag data.
*/
init_rwsem(&mp->m_peraglock);
mp->m_perag =
kmem_zalloc(sbp->sb_agcount * sizeof(xfs_perag_t), KM_SLEEP);
mp->m_maxagi = xfs_initialize_perag(vfsp, mp, sbp->sb_agcount);
/*
* log's mount-time initialization. Perform 1st part recovery if needed
*/
if (likely(sbp->sb_logblocks > 0)) { /* check for volume case */
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) {
cmn_err(CE_WARN, "XFS: log mount failed");
goto error2;
}
} else { /* No log has been defined */
cmn_err(CE_WARN, "XFS: no log defined");
XFS_ERROR_REPORT("xfs_mountfs_int(1)", XFS_ERRLEVEL_LOW, mp);
error = XFS_ERROR(EFSCORRUPTED);
goto error2;
}
/*
* 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, 0);
if (error) {
cmn_err(CE_WARN, "XFS: failed to read root inode");
goto error3;
}
ASSERT(rip != NULL);
rvp = XFS_ITOV(rip);
if (unlikely((rip->i_d.di_mode & S_IFMT) != S_IFDIR)) {
cmn_err(CE_WARN, "XFS: corrupted root inode");
cmn_err(CE_WARN, "Device %s - root %llu is not a directory",
XFS_BUFTARG_NAME(mp->m_ddev_targp),
(unsigned long long)rip->i_ino);
xfs_iunlock(rip, XFS_ILOCK_EXCL);
XFS_ERROR_REPORT("xfs_mountfs_int(2)", XFS_ERRLEVEL_LOW,
mp);
error = XFS_ERROR(EFSCORRUPTED);
goto error4;
}
mp->m_rootip = rip; /* save it */
xfs_iunlock(rip, XFS_ILOCK_EXCL);
/*
* Initialize realtime inode pointers in the mount structure
*/
if ((error = xfs_rtmount_inodes(mp))) {
/*
* Free up the root inode.
*/
cmn_err(CE_WARN, "XFS: failed to read RT inodes");
goto error4;
}
/*
* If fs is not mounted readonly, then update the superblock
* unit and width changes.
*/
if (update_flags && !(vfsp->vfs_flag & VFS_RDONLY))
xfs_mount_log_sbunit(mp, update_flags);
/*
* Initialise the XFS quota management subsystem for this mount
*/
if ((error = XFS_QM_INIT(mp, &quotamount, &quotaflags)))
goto error4;
/*
* 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, mfsi_flags);
if (error) {
cmn_err(CE_WARN, "XFS: log mount finish failed");
goto error4;
}
/*
* Complete the quota initialisation, post-log-replay component.
*/
if ((error = XFS_QM_MOUNT(mp, quotamount, quotaflags, mfsi_flags)))
goto error4;
return 0;
error4:
/*
* Free up the root inode.
*/
VN_RELE(rvp);
error3:
xfs_log_unmount_dealloc(mp);
error2:
xfs_ihash_free(mp);
xfs_chash_free(mp);
for (agno = 0; agno < sbp->sb_agcount; agno++)
if (mp->m_perag[agno].pagb_list)
kmem_free(mp->m_perag[agno].pagb_list,
sizeof(xfs_perag_busy_t) * XFS_PAGB_NUM_SLOTS);
kmem_free(mp->m_perag, sbp->sb_agcount * sizeof(xfs_perag_t));
mp->m_perag = NULL;
/* FALLTHROUGH */
error1:
if (uuid_mounted)
xfs_uuid_unmount(mp);
xfs_freesb(mp);
return error;
}
/*
* xfs_unmountfs
*
* This flushes out the inodes,dquots and the superblock, unmounts the
* log and makes sure that incore structures are freed.
*/
int
xfs_unmountfs(xfs_mount_t *mp, struct cred *cr)
{
struct bhv_vfs *vfsp = XFS_MTOVFS(mp);
#if defined(DEBUG) || defined(INDUCE_IO_ERROR)
int64_t fsid;
#endif
xfs_iflush_all(mp);
XFS_QM_DQPURGEALL(mp, XFS_QMOPT_QUOTALL | XFS_QMOPT_UMOUNTING);
/*
* Flush out the log synchronously so that we know for sure
* that nothing is pinned. This is important because bflush()
* will skip pinned buffers.
*/
xfs_log_force(mp, (xfs_lsn_t)0, XFS_LOG_FORCE | XFS_LOG_SYNC);
xfs_binval(mp->m_ddev_targp);
if (mp->m_rtdev_targp) {
xfs_binval(mp->m_rtdev_targp);
}
xfs_unmountfs_writesb(mp);
xfs_unmountfs_wait(mp); /* wait for async bufs */
xfs_log_unmount(mp); /* Done! No more fs ops. */
xfs_freesb(mp);
/*
* All inodes from this mount point should be freed.
*/
ASSERT(mp->m_inodes == NULL);
xfs_unmountfs_close(mp, cr);
if ((mp->m_flags & XFS_MOUNT_NOUUID) == 0)
xfs_uuid_unmount(mp);
#if defined(DEBUG) || defined(INDUCE_IO_ERROR)
/*
* clear all error tags on this filesystem
*/
memcpy(&fsid, &vfsp->vfs_fsid, sizeof(int64_t));
xfs_errortag_clearall_umount(fsid, mp->m_fsname, 0);
#endif
XFS_IODONE(vfsp);
xfs_mount_free(mp, 1);
return 0;
}
void
xfs_unmountfs_close(xfs_mount_t *mp, struct cred *cr)
{
if (mp->m_logdev_targp != mp->m_ddev_targp)
xfs_free_buftarg(mp->m_logdev_targp, 1);
if (mp->m_rtdev_targp)
xfs_free_buftarg(mp->m_rtdev_targp, 1);
xfs_free_buftarg(mp->m_ddev_targp, 0);
}
STATIC void
xfs_unmountfs_wait(xfs_mount_t *mp)
{
if (mp->m_logdev_targp != mp->m_ddev_targp)
xfs_wait_buftarg(mp->m_logdev_targp);
if (mp->m_rtdev_targp)
xfs_wait_buftarg(mp->m_rtdev_targp);
xfs_wait_buftarg(mp->m_ddev_targp);
}
int
xfs_unmountfs_writesb(xfs_mount_t *mp)
{
xfs_buf_t *sbp;
xfs_sb_t *sb;
int error = 0;
/*
* skip superblock write if fs is read-only, or
* if we are doing a forced umount.
*/
sbp = xfs_getsb(mp, 0);
if (!(XFS_MTOVFS(mp)->vfs_flag & VFS_RDONLY ||
XFS_FORCED_SHUTDOWN(mp))) {
xfs_icsb_sync_counters(mp);
/*
* mark shared-readonly if desired
*/
sb = XFS_BUF_TO_SBP(sbp);
if (mp->m_mk_sharedro) {
if (!(sb->sb_flags & XFS_SBF_READONLY))
sb->sb_flags |= XFS_SBF_READONLY;
if (!XFS_SB_VERSION_HASSHARED(sb))
XFS_SB_VERSION_ADDSHARED(sb);
xfs_fs_cmn_err(CE_NOTE, mp,
"Unmounting, marking shared read-only");
}
XFS_BUF_UNDONE(sbp);
XFS_BUF_UNREAD(sbp);
XFS_BUF_UNDELAYWRITE(sbp);
XFS_BUF_WRITE(sbp);
XFS_BUF_UNASYNC(sbp);
ASSERT(XFS_BUF_TARGET(sbp) == mp->m_ddev_targp);
xfsbdstrat(mp, sbp);
/* Nevermind errors we might get here. */
error = xfs_iowait(sbp);
if (error)
xfs_ioerror_alert("xfs_unmountfs_writesb",
mp, sbp, XFS_BUF_ADDR(sbp));
if (error && mp->m_mk_sharedro)
xfs_fs_cmn_err(CE_ALERT, mp, "Superblock write error detected while unmounting. Filesystem may not be marked shared readonly");
}
xfs_buf_relse(sbp);
return error;
}
/*
* xfs_mod_sb() can be used to copy arbitrary changes to the
* in-core superblock into the superblock buffer to be logged.
* It does not provide the higher level of locking that is
* needed to protect the in-core superblock from concurrent
* access.
*/
void
xfs_mod_sb(xfs_trans_t *tp, __int64_t fields)
{
xfs_buf_t *bp;
int first;
int last;
xfs_mount_t *mp;
xfs_sb_t *sbp;
xfs_sb_field_t f;
ASSERT(fields);
if (!fields)
return;
mp = tp->t_mountp;
bp = xfs_trans_getsb(tp, mp, 0);
sbp = XFS_BUF_TO_SBP(bp);
first = sizeof(xfs_sb_t);
last = 0;
/* translate/copy */
xfs_xlatesb(XFS_BUF_PTR(bp), &(mp->m_sb), -1, fields);
/* find modified range */
f = (xfs_sb_field_t)xfs_lowbit64((__uint64_t)fields);
ASSERT((1LL << f) & XFS_SB_MOD_BITS);
first = xfs_sb_info[f].offset;
f = (xfs_sb_field_t)xfs_highbit64((__uint64_t)fields);
ASSERT((1LL << f) & XFS_SB_MOD_BITS);
last = xfs_sb_info[f + 1].offset - 1;
xfs_trans_log_buf(tp, bp, first, last);
}
/*
* xfs_mod_incore_sb_unlocked() is a utility routine common used to apply
* a delta to a specified field in the in-core superblock. Simply
* switch on the field indicated and apply the delta to that field.
* Fields are not allowed to dip below zero, so if the delta would
* do this do not apply it and return EINVAL.
*
* The SB_LOCK must be held when this routine is called.
*/
int
xfs_mod_incore_sb_unlocked(
xfs_mount_t *mp,
xfs_sb_field_t field,
int64_t delta,
int rsvd)
{
int scounter; /* short counter for 32 bit fields */
long long lcounter; /* long counter for 64 bit fields */
long long res_used, rem;
/*
* With the in-core superblock spin lock held, switch
* on the indicated field. Apply the delta to the
* proper field. If the fields value would dip below
* 0, then do not apply the delta and return EINVAL.
*/
switch (field) {
case XFS_SBS_ICOUNT:
lcounter = (long long)mp->m_sb.sb_icount;
lcounter += delta;
if (lcounter < 0) {
ASSERT(0);
return XFS_ERROR(EINVAL);
}
mp->m_sb.sb_icount = lcounter;
return 0;
case XFS_SBS_IFREE:
lcounter = (long long)mp->m_sb.sb_ifree;
lcounter += delta;
if (lcounter < 0) {
ASSERT(0);
return XFS_ERROR(EINVAL);
}
mp->m_sb.sb_ifree = lcounter;
return 0;
case XFS_SBS_FDBLOCKS:
lcounter = (long long)
mp->m_sb.sb_fdblocks - XFS_ALLOC_SET_ASIDE(mp);
res_used = (long long)(mp->m_resblks - mp->m_resblks_avail);
if (delta > 0) { /* Putting blocks back */
if (res_used > delta) {
mp->m_resblks_avail += delta;
} else {
rem = delta - res_used;
mp->m_resblks_avail = mp->m_resblks;
lcounter += rem;
}
} else { /* Taking blocks away */
lcounter += delta;
/*
* If were out of blocks, use any available reserved blocks if
* were allowed to.
*/
if (lcounter < 0) {
if (rsvd) {
lcounter = (long long)mp->m_resblks_avail + delta;
if (lcounter < 0) {
return XFS_ERROR(ENOSPC);
}
mp->m_resblks_avail = lcounter;
return 0;
} else { /* not reserved */
return XFS_ERROR(ENOSPC);
}
}
}
mp->m_sb.sb_fdblocks = lcounter + XFS_ALLOC_SET_ASIDE(mp);
return 0;
case XFS_SBS_FREXTENTS:
lcounter = (long long)mp->m_sb.sb_frextents;
lcounter += delta;
if (lcounter < 0) {
return XFS_ERROR(ENOSPC);
}
mp->m_sb.sb_frextents = lcounter;
return 0;
case XFS_SBS_DBLOCKS:
lcounter = (long long)mp->m_sb.sb_dblocks;
lcounter += delta;
if (lcounter < 0) {
ASSERT(0);
return XFS_ERROR(EINVAL);
}
mp->m_sb.sb_dblocks = lcounter;
return 0;
case XFS_SBS_AGCOUNT:
scounter = mp->m_sb.sb_agcount;
scounter += delta;
if (scounter < 0) {
ASSERT(0);
return XFS_ERROR(EINVAL);
}
mp->m_sb.sb_agcount = scounter;
return 0;
case XFS_SBS_IMAX_PCT:
scounter = mp->m_sb.sb_imax_pct;
scounter += delta;
if (scounter < 0) {
ASSERT(0);
return XFS_ERROR(EINVAL);
}
mp->m_sb.sb_imax_pct = scounter;
return 0;
case XFS_SBS_REXTSIZE:
scounter = mp->m_sb.sb_rextsize;
scounter += delta;
if (scounter < 0) {
ASSERT(0);
return XFS_ERROR(EINVAL);
}
mp->m_sb.sb_rextsize = scounter;
return 0;
case XFS_SBS_RBMBLOCKS:
scounter = mp->m_sb.sb_rbmblocks;
scounter += delta;
if (scounter < 0) {
ASSERT(0);
return XFS_ERROR(EINVAL);
}
mp->m_sb.sb_rbmblocks = scounter;
return 0;
case XFS_SBS_RBLOCKS:
lcounter = (long long)mp->m_sb.sb_rblocks;
lcounter += delta;
if (lcounter < 0) {
ASSERT(0);
return XFS_ERROR(EINVAL);
}
mp->m_sb.sb_rblocks = lcounter;
return 0;
case XFS_SBS_REXTENTS:
lcounter = (long long)mp->m_sb.sb_rextents;
lcounter += delta;
if (lcounter < 0) {
ASSERT(0);
return XFS_ERROR(EINVAL);
}
mp->m_sb.sb_rextents = lcounter;
return 0;
case XFS_SBS_REXTSLOG:
scounter = mp->m_sb.sb_rextslog;
scounter += delta;
if (scounter < 0) {
ASSERT(0);
return XFS_ERROR(EINVAL);
}
mp->m_sb.sb_rextslog = scounter;
return 0;
default:
ASSERT(0);
return XFS_ERROR(EINVAL);
}
}
/*
* xfs_mod_incore_sb() is used to change a field in the in-core
* superblock structure by the specified delta. This modification
* is protected by the SB_LOCK. Just use the xfs_mod_incore_sb_unlocked()
* routine to do the work.
*/
int
xfs_mod_incore_sb(
xfs_mount_t *mp,
xfs_sb_field_t field,
int64_t delta,
int rsvd)
{
unsigned long s;
int status;
/* check for per-cpu counters */
switch (field) {
#ifdef HAVE_PERCPU_SB
case XFS_SBS_ICOUNT:
case XFS_SBS_IFREE:
case XFS_SBS_FDBLOCKS:
if (!(mp->m_flags & XFS_MOUNT_NO_PERCPU_SB)) {
status = xfs_icsb_modify_counters(mp, field,
delta, rsvd);
break;
}
/* FALLTHROUGH */
#endif
default:
s = XFS_SB_LOCK(mp);
status = xfs_mod_incore_sb_unlocked(mp, field, delta, rsvd);
XFS_SB_UNLOCK(mp, s);
break;
}
return status;
}
/*
* xfs_mod_incore_sb_batch() is used to change more than one field
* in the in-core superblock structure at a time. This modification
* is protected by a lock internal to this module. The fields and
* changes to those fields are specified in the array of xfs_mod_sb
* structures passed in.
*
* Either all of the specified deltas will be applied or none of
* them will. If any modified field dips below 0, then all modifications
* will be backed out and EINVAL will be returned.
*/
int
xfs_mod_incore_sb_batch(xfs_mount_t *mp, xfs_mod_sb_t *msb, uint nmsb, int rsvd)
{
unsigned long s;
int status=0;
xfs_mod_sb_t *msbp;
/*
* Loop through the array of mod structures and apply each
* individually. If any fail, then back out all those
* which have already been applied. Do all of this within
* the scope of the SB_LOCK so that all of the changes will
* be atomic.
*/
s = XFS_SB_LOCK(mp);
msbp = &msb[0];
for (msbp = &msbp[0]; msbp < (msb + nmsb); msbp++) {
/*
* Apply the delta at index n. If it fails, break
* from the loop so we'll fall into the undo loop
* below.
*/
switch (msbp->msb_field) {
#ifdef HAVE_PERCPU_SB
case XFS_SBS_ICOUNT:
case XFS_SBS_IFREE:
case XFS_SBS_FDBLOCKS:
if (!(mp->m_flags & XFS_MOUNT_NO_PERCPU_SB)) {
XFS_SB_UNLOCK(mp, s);
status = xfs_icsb_modify_counters(mp,
msbp->msb_field,
msbp->msb_delta, rsvd);
s = XFS_SB_LOCK(mp);
break;
}
/* FALLTHROUGH */
#endif
default:
status = xfs_mod_incore_sb_unlocked(mp,
msbp->msb_field,
msbp->msb_delta, rsvd);
break;
}
if (status != 0) {
break;
}
}
/*
* If we didn't complete the loop above, then back out
* any changes made to the superblock. If you add code
* between the loop above and here, make sure that you
* preserve the value of status. Loop back until
* we step below the beginning of the array. Make sure
* we don't touch anything back there.
*/
if (status != 0) {
msbp--;
while (msbp >= msb) {
switch (msbp->msb_field) {
#ifdef HAVE_PERCPU_SB
case XFS_SBS_ICOUNT:
case XFS_SBS_IFREE:
case XFS_SBS_FDBLOCKS:
if (!(mp->m_flags & XFS_MOUNT_NO_PERCPU_SB)) {
XFS_SB_UNLOCK(mp, s);
status = xfs_icsb_modify_counters(mp,
msbp->msb_field,
-(msbp->msb_delta),
rsvd);
s = XFS_SB_LOCK(mp);
break;
}
/* FALLTHROUGH */
#endif
default:
status = xfs_mod_incore_sb_unlocked(mp,
msbp->msb_field,
-(msbp->msb_delta),
rsvd);
break;
}
ASSERT(status == 0);
msbp--;
}
}
XFS_SB_UNLOCK(mp, s);
return status;
}
/*
* 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.
*/
xfs_buf_t *
xfs_getsb(
xfs_mount_t *mp,
int flags)
{
xfs_buf_t *bp;
ASSERT(mp->m_sb_bp != NULL);
bp = mp->m_sb_bp;
if (flags & XFS_BUF_TRYLOCK) {
if (!XFS_BUF_CPSEMA(bp)) {
return NULL;
}
} else {
XFS_BUF_PSEMA(bp, PRIBIO);
}
XFS_BUF_HOLD(bp);
ASSERT(XFS_BUF_ISDONE(bp));
return bp;
}
/*
* Used to free the superblock along various error paths.
*/
void
xfs_freesb(
xfs_mount_t *mp)
{
xfs_buf_t *bp;
/*
* Use xfs_getsb() so that the buffer will be locked
* when we call xfs_buf_relse().
*/
bp = xfs_getsb(mp, 0);
XFS_BUF_UNMANAGE(bp);
xfs_buf_relse(bp);
mp->m_sb_bp = NULL;
}
/*
* 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(
xfs_mount_t *mp)
{
if (uuid_is_nil(&mp->m_sb.sb_uuid)) {
cmn_err(CE_WARN,
"XFS: Filesystem %s has nil UUID - can't mount",
mp->m_fsname);
return -1;
}
if (!uuid_table_insert(&mp->m_sb.sb_uuid)) {
cmn_err(CE_WARN,
"XFS: Filesystem %s has duplicate UUID - can't mount",
mp->m_fsname);
return -1;
}
return 0;
}
/*
* Remove filesystem from the UUID table.
*/
STATIC void
xfs_uuid_unmount(
xfs_mount_t *mp)
{
uuid_table_remove(&mp->m_sb.sb_uuid);
}
/*
* Used to log changes to the superblock unit and width fields which could
* be altered by the mount options. Only the first superblock is updated.
*/
STATIC void
xfs_mount_log_sbunit(
xfs_mount_t *mp,
__int64_t fields)
{
xfs_trans_t *tp;
ASSERT(fields & (XFS_SB_UNIT|XFS_SB_WIDTH|XFS_SB_UUID));
tp = xfs_trans_alloc(mp, XFS_TRANS_SB_UNIT);
if (xfs_trans_reserve(tp, 0, mp->m_sb.sb_sectsize + 128, 0, 0,
XFS_DEFAULT_LOG_COUNT)) {
xfs_trans_cancel(tp, 0);
return;
}
xfs_mod_sb(tp, fields);
xfs_trans_commit(tp, 0);
}
#ifdef HAVE_PERCPU_SB
/*
* Per-cpu incore superblock counters
*
* Simple concept, difficult implementation
*
* Basically, replace the incore superblock counters with a distributed per cpu
* counter for contended fields (e.g. free block count).
*
* Difficulties arise in that the incore sb is used for ENOSPC checking, and
* hence needs to be accurately read when we are running low on space. Hence
* there is a method to enable and disable the per-cpu counters based on how
* much "stuff" is available in them.
*
* Basically, a counter is enabled if there is enough free resource to justify
* running a per-cpu fast-path. If the per-cpu counter runs out (i.e. a local
* ENOSPC), then we disable the counters to synchronise all callers and
* re-distribute the available resources.
*
* If, once we redistributed the available resources, we still get a failure,
* we disable the per-cpu counter and go through the slow path.
*
* The slow path is the current xfs_mod_incore_sb() function. This means that
* when we disable a per-cpu counter, we need to drain it's resources back to
* the global superblock. We do this after disabling the counter to prevent
* more threads from queueing up on the counter.
*
* Essentially, this means that we still need a lock in the fast path to enable
* synchronisation between the global counters and the per-cpu counters. This
* is not a problem because the lock will be local to a CPU almost all the time
* and have little contention except when we get to ENOSPC conditions.
*
* Basically, this lock becomes a barrier that enables us to lock out the fast
* path while we do things like enabling and disabling counters and
* synchronising the counters.
*
* Locking rules:
*
* 1. XFS_SB_LOCK() before picking up per-cpu locks
* 2. per-cpu locks always picked up via for_each_online_cpu() order
* 3. accurate counter sync requires XFS_SB_LOCK + per cpu locks
* 4. modifying per-cpu counters requires holding per-cpu lock
* 5. modifying global counters requires holding XFS_SB_LOCK
* 6. enabling or disabling a counter requires holding the XFS_SB_LOCK
* and _none_ of the per-cpu locks.
*
* Disabled counters are only ever re-enabled by a balance operation
* that results in more free resources per CPU than a given threshold.
* To ensure counters don't remain disabled, they are rebalanced when
* the global resource goes above a higher threshold (i.e. some hysteresis
* is present to prevent thrashing).
*/
#ifdef CONFIG_HOTPLUG_CPU
/*
* hot-plug CPU notifier support.
*
* We need a notifier per filesystem as we need to be able to identify
* the filesystem to balance the counters out. This is achieved by
* having a notifier block embedded in the xfs_mount_t and doing pointer
* magic to get the mount pointer from the notifier block address.
*/
STATIC int
xfs_icsb_cpu_notify(
struct notifier_block *nfb,
unsigned long action,
void *hcpu)
{
xfs_icsb_cnts_t *cntp;
xfs_mount_t *mp;
int s;
mp = (xfs_mount_t *)container_of(nfb, xfs_mount_t, m_icsb_notifier);
cntp = (xfs_icsb_cnts_t *)
per_cpu_ptr(mp->m_sb_cnts, (unsigned long)hcpu);
switch (action) {
case CPU_UP_PREPARE:
/* Easy Case - initialize the area and locks, and
* then rebalance when online does everything else for us. */
memset(cntp, 0, sizeof(xfs_icsb_cnts_t));
break;
case CPU_ONLINE:
xfs_icsb_lock(mp);
xfs_icsb_balance_counter(mp, XFS_SBS_ICOUNT, 0, 0);
xfs_icsb_balance_counter(mp, XFS_SBS_IFREE, 0, 0);
xfs_icsb_balance_counter(mp, XFS_SBS_FDBLOCKS, 0, 0);
xfs_icsb_unlock(mp);
break;
case CPU_DEAD:
/* Disable all the counters, then fold the dead cpu's
* count into the total on the global superblock and
* re-enable the counters. */
xfs_icsb_lock(mp);
s = XFS_SB_LOCK(mp);
xfs_icsb_disable_counter(mp, XFS_SBS_ICOUNT);
xfs_icsb_disable_counter(mp, XFS_SBS_IFREE);
xfs_icsb_disable_counter(mp, XFS_SBS_FDBLOCKS);
mp->m_sb.sb_icount += cntp->icsb_icount;
mp->m_sb.sb_ifree += cntp->icsb_ifree;
mp->m_sb.sb_fdblocks += cntp->icsb_fdblocks;
memset(cntp, 0, sizeof(xfs_icsb_cnts_t));
xfs_icsb_balance_counter(mp, XFS_SBS_ICOUNT,
XFS_ICSB_SB_LOCKED, 0);
xfs_icsb_balance_counter(mp, XFS_SBS_IFREE,
XFS_ICSB_SB_LOCKED, 0);
xfs_icsb_balance_counter(mp, XFS_SBS_FDBLOCKS,
XFS_ICSB_SB_LOCKED, 0);
XFS_SB_UNLOCK(mp, s);
xfs_icsb_unlock(mp);
break;
}
return NOTIFY_OK;
}
#endif /* CONFIG_HOTPLUG_CPU */
int
xfs_icsb_init_counters(
xfs_mount_t *mp)
{
xfs_icsb_cnts_t *cntp;
int i;
mp->m_sb_cnts = alloc_percpu(xfs_icsb_cnts_t);
if (mp->m_sb_cnts == NULL)
return -ENOMEM;
#ifdef CONFIG_HOTPLUG_CPU
mp->m_icsb_notifier.notifier_call = xfs_icsb_cpu_notify;
mp->m_icsb_notifier.priority = 0;
register_hotcpu_notifier(&mp->m_icsb_notifier);
#endif /* CONFIG_HOTPLUG_CPU */
for_each_online_cpu(i) {
cntp = (xfs_icsb_cnts_t *)per_cpu_ptr(mp->m_sb_cnts, i);
memset(cntp, 0, sizeof(xfs_icsb_cnts_t));
}
mutex_init(&mp->m_icsb_mutex);
/*
* start with all counters disabled so that the
* initial balance kicks us off correctly
*/
mp->m_icsb_counters = -1;
return 0;
}
void
xfs_icsb_reinit_counters(
xfs_mount_t *mp)
{
xfs_icsb_lock(mp);
/*
* start with all counters disabled so that the
* initial balance kicks us off correctly
*/
mp->m_icsb_counters = -1;
xfs_icsb_balance_counter(mp, XFS_SBS_ICOUNT, 0, 0);
xfs_icsb_balance_counter(mp, XFS_SBS_IFREE, 0, 0);
xfs_icsb_balance_counter(mp, XFS_SBS_FDBLOCKS, 0, 0);
xfs_icsb_unlock(mp);
}
STATIC void
xfs_icsb_destroy_counters(
xfs_mount_t *mp)
{
if (mp->m_sb_cnts) {
unregister_hotcpu_notifier(&mp->m_icsb_notifier);
free_percpu(mp->m_sb_cnts);
}
mutex_destroy(&mp->m_icsb_mutex);
}
STATIC_INLINE void
xfs_icsb_lock_cntr(
xfs_icsb_cnts_t *icsbp)
{
while (test_and_set_bit(XFS_ICSB_FLAG_LOCK, &icsbp->icsb_flags)) {
ndelay(1000);
}
}
STATIC_INLINE void
xfs_icsb_unlock_cntr(
xfs_icsb_cnts_t *icsbp)
{
clear_bit(XFS_ICSB_FLAG_LOCK, &icsbp->icsb_flags);
}
STATIC_INLINE void
xfs_icsb_lock_all_counters(
xfs_mount_t *mp)
{
xfs_icsb_cnts_t *cntp;
int i;
for_each_online_cpu(i) {
cntp = (xfs_icsb_cnts_t *)per_cpu_ptr(mp->m_sb_cnts, i);
xfs_icsb_lock_cntr(cntp);
}
}
STATIC_INLINE void
xfs_icsb_unlock_all_counters(
xfs_mount_t *mp)
{
xfs_icsb_cnts_t *cntp;
int i;
for_each_online_cpu(i) {
cntp = (xfs_icsb_cnts_t *)per_cpu_ptr(mp->m_sb_cnts, i);
xfs_icsb_unlock_cntr(cntp);
}
}
STATIC void
xfs_icsb_count(
xfs_mount_t *mp,
xfs_icsb_cnts_t *cnt,
int flags)
{
xfs_icsb_cnts_t *cntp;
int i;
memset(cnt, 0, sizeof(xfs_icsb_cnts_t));
if (!(flags & XFS_ICSB_LAZY_COUNT))
xfs_icsb_lock_all_counters(mp);
for_each_online_cpu(i) {
cntp = (xfs_icsb_cnts_t *)per_cpu_ptr(mp->m_sb_cnts, i);
cnt->icsb_icount += cntp->icsb_icount;
cnt->icsb_ifree += cntp->icsb_ifree;
cnt->icsb_fdblocks += cntp->icsb_fdblocks;
}
if (!(flags & XFS_ICSB_LAZY_COUNT))
xfs_icsb_unlock_all_counters(mp);
}
STATIC int
xfs_icsb_counter_disabled(
xfs_mount_t *mp,
xfs_sb_field_t field)
{
ASSERT((field >= XFS_SBS_ICOUNT) && (field <= XFS_SBS_FDBLOCKS));
return test_bit(field, &mp->m_icsb_counters);
}
STATIC int
xfs_icsb_disable_counter(
xfs_mount_t *mp,
xfs_sb_field_t field)
{
xfs_icsb_cnts_t cnt;
ASSERT((field >= XFS_SBS_ICOUNT) && (field <= XFS_SBS_FDBLOCKS));
/*
* If we are already disabled, then there is nothing to do
* here. We check before locking all the counters to avoid
* the expensive lock operation when being called in the
* slow path and the counter is already disabled. This is
* safe because the only time we set or clear this state is under
* the m_icsb_mutex.
*/
if (xfs_icsb_counter_disabled(mp, field))
return 0;
xfs_icsb_lock_all_counters(mp);
if (!test_and_set_bit(field, &mp->m_icsb_counters)) {
/* drain back to superblock */
xfs_icsb_count(mp, &cnt, XFS_ICSB_SB_LOCKED|XFS_ICSB_LAZY_COUNT);
switch(field) {
case XFS_SBS_ICOUNT:
mp->m_sb.sb_icount = cnt.icsb_icount;
break;
case XFS_SBS_IFREE:
mp->m_sb.sb_ifree = cnt.icsb_ifree;
break;
case XFS_SBS_FDBLOCKS:
mp->m_sb.sb_fdblocks = cnt.icsb_fdblocks;
break;
default:
BUG();
}
}
xfs_icsb_unlock_all_counters(mp);
return 0;
}
STATIC void
xfs_icsb_enable_counter(
xfs_mount_t *mp,
xfs_sb_field_t field,
uint64_t count,
uint64_t resid)
{
xfs_icsb_cnts_t *cntp;
int i;
ASSERT((field >= XFS_SBS_ICOUNT) && (field <= XFS_SBS_FDBLOCKS));
xfs_icsb_lock_all_counters(mp);
for_each_online_cpu(i) {
cntp = per_cpu_ptr(mp->m_sb_cnts, i);
switch (field) {
case XFS_SBS_ICOUNT:
cntp->icsb_icount = count + resid;
break;
case XFS_SBS_IFREE:
cntp->icsb_ifree = count + resid;
break;
case XFS_SBS_FDBLOCKS:
cntp->icsb_fdblocks = count + resid;
break;
default:
BUG();
break;
}
resid = 0;
}
clear_bit(field, &mp->m_icsb_counters);
xfs_icsb_unlock_all_counters(mp);
}
void
xfs_icsb_sync_counters_flags(
xfs_mount_t *mp,
int flags)
{
xfs_icsb_cnts_t cnt;
int s;
/* Pass 1: lock all counters */
if ((flags & XFS_ICSB_SB_LOCKED) == 0)
s = XFS_SB_LOCK(mp);
xfs_icsb_count(mp, &cnt, flags);
/* Step 3: update mp->m_sb fields */
if (!xfs_icsb_counter_disabled(mp, XFS_SBS_ICOUNT))
mp->m_sb.sb_icount = cnt.icsb_icount;
if (!xfs_icsb_counter_disabled(mp, XFS_SBS_IFREE))
mp->m_sb.sb_ifree = cnt.icsb_ifree;
if (!xfs_icsb_counter_disabled(mp, XFS_SBS_FDBLOCKS))
mp->m_sb.sb_fdblocks = cnt.icsb_fdblocks;
if ((flags & XFS_ICSB_SB_LOCKED) == 0)
XFS_SB_UNLOCK(mp, s);
}
/*
* Accurate update of per-cpu counters to incore superblock
*/
STATIC void
xfs_icsb_sync_counters(
xfs_mount_t *mp)
{
xfs_icsb_sync_counters_flags(mp, 0);
}
/*
* Balance and enable/disable counters as necessary.
*
* Thresholds for re-enabling counters are somewhat magic. inode counts are
* chosen to be the same number as single on disk allocation chunk per CPU, and
* free blocks is something far enough zero that we aren't going thrash when we
* get near ENOSPC. We also need to supply a minimum we require per cpu to
* prevent looping endlessly when xfs_alloc_space asks for more than will
* be distributed to a single CPU but each CPU has enough blocks to be
* reenabled.
*
* Note that we can be called when counters are already disabled.
* xfs_icsb_disable_counter() optimises the counter locking in this case to
* prevent locking every per-cpu counter needlessly.
*/
#define XFS_ICSB_INO_CNTR_REENABLE (uint64_t)64
#define XFS_ICSB_FDBLK_CNTR_REENABLE(mp) \
(uint64_t)(512 + XFS_ALLOC_SET_ASIDE(mp))
STATIC void
xfs_icsb_balance_counter(
xfs_mount_t *mp,
xfs_sb_field_t field,
int flags,
int min_per_cpu)
{
uint64_t count, resid;
int weight = num_online_cpus();
int s;
uint64_t min = (uint64_t)min_per_cpu;
if (!(flags & XFS_ICSB_SB_LOCKED))
s = XFS_SB_LOCK(mp);
/* disable counter and sync counter */
xfs_icsb_disable_counter(mp, field);
/* update counters - first CPU gets residual*/
switch (field) {
case XFS_SBS_ICOUNT:
count = mp->m_sb.sb_icount;
resid = do_div(count, weight);
if (count < max(min, XFS_ICSB_INO_CNTR_REENABLE))
goto out;
break;
case XFS_SBS_IFREE:
count = mp->m_sb.sb_ifree;
resid = do_div(count, weight);
if (count < max(min, XFS_ICSB_INO_CNTR_REENABLE))
goto out;
break;
case XFS_SBS_FDBLOCKS:
count = mp->m_sb.sb_fdblocks;
resid = do_div(count, weight);
if (count < max(min, XFS_ICSB_FDBLK_CNTR_REENABLE(mp)))
goto out;
break;
default:
BUG();
count = resid = 0; /* quiet, gcc */
break;
}
xfs_icsb_enable_counter(mp, field, count, resid);
out:
if (!(flags & XFS_ICSB_SB_LOCKED))
XFS_SB_UNLOCK(mp, s);
}
int
xfs_icsb_modify_counters(
xfs_mount_t *mp,
xfs_sb_field_t field,
int64_t delta,
int rsvd)
{
xfs_icsb_cnts_t *icsbp;
long long lcounter; /* long counter for 64 bit fields */
int cpu, ret = 0, s;
might_sleep();
again:
cpu = get_cpu();
icsbp = (xfs_icsb_cnts_t *)per_cpu_ptr(mp->m_sb_cnts, cpu);
/*
* if the counter is disabled, go to slow path
*/
if (unlikely(xfs_icsb_counter_disabled(mp, field)))
goto slow_path;
xfs_icsb_lock_cntr(icsbp);
if (unlikely(xfs_icsb_counter_disabled(mp, field))) {
xfs_icsb_unlock_cntr(icsbp);
goto slow_path;
}
switch (field) {
case XFS_SBS_ICOUNT:
lcounter = icsbp->icsb_icount;
lcounter += delta;
if (unlikely(lcounter < 0))
goto balance_counter;
icsbp->icsb_icount = lcounter;
break;
case XFS_SBS_IFREE:
lcounter = icsbp->icsb_ifree;
lcounter += delta;
if (unlikely(lcounter < 0))
goto balance_counter;
icsbp->icsb_ifree = lcounter;
break;
case XFS_SBS_FDBLOCKS:
BUG_ON((mp->m_resblks - mp->m_resblks_avail) != 0);
lcounter = icsbp->icsb_fdblocks - XFS_ALLOC_SET_ASIDE(mp);
lcounter += delta;
if (unlikely(lcounter < 0))
goto balance_counter;
icsbp->icsb_fdblocks = lcounter + XFS_ALLOC_SET_ASIDE(mp);
break;
default:
BUG();
break;
}
xfs_icsb_unlock_cntr(icsbp);
put_cpu();
return 0;
slow_path:
put_cpu();
/*
* serialise with a mutex so we don't burn lots of cpu on
* the superblock lock. We still need to hold the superblock
* lock, however, when we modify the global structures.
*/
xfs_icsb_lock(mp);
/*
* Now running atomically.
*
* If the counter is enabled, someone has beaten us to rebalancing.
* Drop the lock and try again in the fast path....
*/
if (!(xfs_icsb_counter_disabled(mp, field))) {
xfs_icsb_unlock(mp);
goto again;
}
/*
* The counter is currently disabled. Because we are
* running atomically here, we know a rebalance cannot
* be in progress. Hence we can go straight to operating
* on the global superblock. We do not call xfs_mod_incore_sb()
* here even though we need to get the SB_LOCK. Doing so
* will cause us to re-enter this function and deadlock.
* Hence we get the SB_LOCK ourselves and then call
* xfs_mod_incore_sb_unlocked() as the unlocked path operates
* directly on the global counters.
*/
s = XFS_SB_LOCK(mp);
ret = xfs_mod_incore_sb_unlocked(mp, field, delta, rsvd);
XFS_SB_UNLOCK(mp, s);
/*
* Now that we've modified the global superblock, we
* may be able to re-enable the distributed counters
* (e.g. lots of space just got freed). After that
* we are done.
*/
if (ret != ENOSPC)
xfs_icsb_balance_counter(mp, field, 0, 0);
xfs_icsb_unlock(mp);
return ret;
balance_counter:
xfs_icsb_unlock_cntr(icsbp);
put_cpu();
/*
* We may have multiple threads here if multiple per-cpu
* counters run dry at the same time. This will mean we can
* do more balances than strictly necessary but it is not
* the common slowpath case.
*/
xfs_icsb_lock(mp);
/*
* running atomically.
*
* This will leave the counter in the correct state for future
* accesses. After the rebalance, we simply try again and our retry
* will either succeed through the fast path or slow path without
* another balance operation being required.
*/
xfs_icsb_balance_counter(mp, field, 0, delta);
xfs_icsb_unlock(mp);
goto again;
}
#endif