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alistair23-linux/fs/xfs/xfs_mount.h
Christoph Hellwig 66ae56a53f xfs: introduce an always_cow mode 
Add a mode where XFS never overwrites existing blocks in place.  This
is to aid debugging our COW code, and also put infatructure in place
for things like possible future support for zoned block devices, which
can't support overwrites.

This mode is enabled globally by doing a:

    echo 1 > /sys/fs/xfs/debug/always_cow

Note that the parameter is global to allow running all tests in xfstests
easily in this mode, which would not easily be possible with a per-fs
sysfs file.

In always_cow mode persistent preallocations are disabled, and fallocate
will fail when called with a 0 mode (with our without
FALLOC_FL_KEEP_SIZE), and not create unwritten extent for zeroed space
when called with FALLOC_FL_ZERO_RANGE or FALLOC_FL_UNSHARE_RANGE.

There are a few interesting xfstests failures when run in always_cow
mode:

 - generic/392 fails because the bytes used in the file used to test
   hole punch recovery are less after the log replay.  This is
   because the blocks written and then punched out are only freed
   with a delay due to the logging mechanism.
 - xfs/170 will fail as the already fragile file streams mechanism
   doesn't seem to interact well with the COW allocator
 - xfs/180 xfs/182 xfs/192 xfs/198 xfs/204 and xfs/208 will claim
   the file system is badly fragmented, but there is not much we
   can do to avoid that when always writing out of place
 - xfs/205 fails because overwriting a file in always_cow mode
   will require new space allocation and the assumption in the
   test thus don't work anymore.
 - xfs/326 fails to modify the file at all in always_cow mode after
   injecting the refcount error, leading to an unexpected md5sum
   after the remount, but that again is expected

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
2019-02-21 07:55:07 -08:00

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// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (c) 2000-2005 Silicon Graphics, Inc.
* All Rights Reserved.
*/
#ifndef __XFS_MOUNT_H__
#define __XFS_MOUNT_H__
struct xlog;
struct xfs_inode;
struct xfs_mru_cache;
struct xfs_nameops;
struct xfs_ail;
struct xfs_quotainfo;
struct xfs_dir_ops;
struct xfs_da_geometry;
/* dynamic preallocation free space thresholds, 5% down to 1% */
enum {
XFS_LOWSP_1_PCNT = 0,
XFS_LOWSP_2_PCNT,
XFS_LOWSP_3_PCNT,
XFS_LOWSP_4_PCNT,
XFS_LOWSP_5_PCNT,
XFS_LOWSP_MAX,
};
/*
* Error Configuration
*
* Error classes define the subsystem the configuration belongs to.
* Error numbers define the errors that are configurable.
*/
enum {
XFS_ERR_METADATA,
XFS_ERR_CLASS_MAX,
};
enum {
XFS_ERR_DEFAULT,
XFS_ERR_EIO,
XFS_ERR_ENOSPC,
XFS_ERR_ENODEV,
XFS_ERR_ERRNO_MAX,
};
#define XFS_ERR_RETRY_FOREVER -1
/*
* Although retry_timeout is in jiffies which is normally an unsigned long,
* we limit the retry timeout to 86400 seconds, or one day. So even a
* signed 32-bit long is sufficient for a HZ value up to 24855. Making it
* signed lets us store the special "-1" value, meaning retry forever.
*/
struct xfs_error_cfg {
struct xfs_kobj kobj;
int max_retries;
long retry_timeout; /* in jiffies, -1 = infinite */
};
typedef struct xfs_mount {
struct super_block *m_super;
xfs_tid_t m_tid; /* next unused tid for fs */
struct xfs_ail *m_ail; /* fs active log item list */
struct xfs_sb m_sb; /* copy of fs superblock */
spinlock_t m_sb_lock; /* sb counter lock */
struct percpu_counter m_icount; /* allocated inodes counter */
struct percpu_counter m_ifree; /* free inodes counter */
struct percpu_counter m_fdblocks; /* free block counter */
struct xfs_buf *m_sb_bp; /* buffer for superblock */
char *m_fsname; /* filesystem name */
int m_fsname_len; /* strlen of fs name */
char *m_rtname; /* realtime device name */
char *m_logname; /* external log device name */
int m_bsize; /* fs logical block size */
xfs_agnumber_t m_agfrotor; /* last ag where space found */
xfs_agnumber_t m_agirotor; /* last ag dir inode alloced */
spinlock_t m_agirotor_lock;/* .. and lock protecting it */
xfs_agnumber_t m_maxagi; /* highest inode alloc group */
uint m_readio_log; /* min read size log bytes */
uint m_readio_blocks; /* min read size blocks */
uint m_writeio_log; /* min write size log bytes */
uint m_writeio_blocks; /* min write size blocks */
struct xfs_da_geometry *m_dir_geo; /* directory block geometry */
struct xfs_da_geometry *m_attr_geo; /* attribute block geometry */
struct xlog *m_log; /* log specific stuff */
int m_logbufs; /* number of log buffers */
int m_logbsize; /* size of each log buffer */
uint m_rsumlevels; /* rt summary levels */
uint m_rsumsize; /* size of rt summary, bytes */
/*
* Optional cache of rt summary level per bitmap block with the
* invariant that m_rsum_cache[bbno] <= the minimum i for which
* rsum[i][bbno] != 0. Reads and writes are serialized by the rsumip
* inode lock.
*/
uint8_t *m_rsum_cache;
struct xfs_inode *m_rbmip; /* pointer to bitmap inode */
struct xfs_inode *m_rsumip; /* pointer to summary inode */
struct xfs_inode *m_rootip; /* pointer to root directory */
struct xfs_quotainfo *m_quotainfo; /* disk quota information */
xfs_buftarg_t *m_ddev_targp; /* saves taking the address */
xfs_buftarg_t *m_logdev_targp;/* ptr to log device */
xfs_buftarg_t *m_rtdev_targp; /* ptr to rt device */
uint8_t m_blkbit_log; /* blocklog + NBBY */
uint8_t m_blkbb_log; /* blocklog - BBSHIFT */
uint8_t m_agno_log; /* log #ag's */
uint8_t m_agino_log; /* #bits for agino in inum */
uint m_inode_cluster_size;/* min inode buf size */
unsigned int m_inodes_per_cluster;
unsigned int m_blocks_per_cluster;
unsigned int m_cluster_align;
unsigned int m_cluster_align_inodes;
uint m_blockmask; /* sb_blocksize-1 */
uint m_blockwsize; /* sb_blocksize in words */
uint m_blockwmask; /* blockwsize-1 */
uint m_alloc_mxr[2]; /* max alloc btree records */
uint m_alloc_mnr[2]; /* min alloc btree records */
uint m_bmap_dmxr[2]; /* max bmap btree records */
uint m_bmap_dmnr[2]; /* min bmap btree records */
uint m_inobt_mxr[2]; /* max inobt btree records */
uint m_inobt_mnr[2]; /* min inobt btree records */
uint m_rmap_mxr[2]; /* max rmap btree records */
uint m_rmap_mnr[2]; /* min rmap btree records */
uint m_refc_mxr[2]; /* max refc btree records */
uint m_refc_mnr[2]; /* min refc btree records */
uint m_ag_maxlevels; /* XFS_AG_MAXLEVELS */
uint m_bm_maxlevels[2]; /* XFS_BM_MAXLEVELS */
uint m_in_maxlevels; /* max inobt btree levels. */
uint m_rmap_maxlevels; /* max rmap btree levels */
uint m_refc_maxlevels; /* max refcount btree level */
xfs_extlen_t m_ag_prealloc_blocks; /* reserved ag blocks */
uint m_alloc_set_aside; /* space we can't use */
uint m_ag_max_usable; /* max space per AG */
struct radix_tree_root m_perag_tree; /* per-ag accounting info */
spinlock_t m_perag_lock; /* lock for m_perag_tree */
struct mutex m_growlock; /* growfs mutex */
int m_fixedfsid[2]; /* unchanged for life of FS */
uint64_t m_flags; /* global mount flags */
bool m_finobt_nores; /* no per-AG finobt resv. */
int m_ialloc_inos; /* inodes in inode allocation */
int m_ialloc_blks; /* blocks in inode allocation */
int m_ialloc_min_blks;/* min blocks in sparse inode
* allocation */
int m_inoalign_mask;/* mask sb_inoalignmt if used */
uint m_qflags; /* quota status flags */
struct xfs_trans_resv m_resv; /* precomputed res values */
uint64_t m_maxicount; /* maximum inode count */
uint64_t m_resblks; /* total reserved blocks */
uint64_t m_resblks_avail;/* available reserved blocks */
uint64_t m_resblks_save; /* reserved blks @ remount,ro */
int m_dalign; /* stripe unit */
int m_swidth; /* stripe width */
int m_sinoalign; /* stripe unit inode alignment */
uint8_t m_sectbb_log; /* sectlog - BBSHIFT */
const struct xfs_nameops *m_dirnameops; /* vector of dir name ops */
const struct xfs_dir_ops *m_dir_inode_ops; /* vector of dir inode ops */
const struct xfs_dir_ops *m_nondir_inode_ops; /* !dir inode ops */
uint m_chsize; /* size of next field */
atomic_t m_active_trans; /* number trans frozen */
struct xfs_mru_cache *m_filestream; /* per-mount filestream data */
struct delayed_work m_reclaim_work; /* background inode reclaim */
struct delayed_work m_eofblocks_work; /* background eof blocks
trimming */
struct delayed_work m_cowblocks_work; /* background cow blocks
trimming */
bool m_update_sb; /* sb needs update in mount */
int64_t m_low_space[XFS_LOWSP_MAX];
/* low free space thresholds */
struct xfs_kobj m_kobj;
struct xfs_kobj m_error_kobj;
struct xfs_kobj m_error_meta_kobj;
struct xfs_error_cfg m_error_cfg[XFS_ERR_CLASS_MAX][XFS_ERR_ERRNO_MAX];
struct xstats m_stats; /* per-fs stats */
struct workqueue_struct *m_buf_workqueue;
struct workqueue_struct *m_data_workqueue;
struct workqueue_struct *m_unwritten_workqueue;
struct workqueue_struct *m_cil_workqueue;
struct workqueue_struct *m_reclaim_workqueue;
struct workqueue_struct *m_log_workqueue;
struct workqueue_struct *m_eofblocks_workqueue;
struct workqueue_struct *m_sync_workqueue;
/*
* Generation of the filesysyem layout. This is incremented by each
* growfs, and used by the pNFS server to ensure the client updates
* its view of the block device once it gets a layout that might
* reference the newly added blocks. Does not need to be persistent
* as long as we only allow file system size increments, but if we
* ever support shrinks it would have to be persisted in addition
* to various other kinds of pain inflicted on the pNFS server.
*/
uint32_t m_generation;
bool m_always_cow;
bool m_fail_unmount;
#ifdef DEBUG
/*
* Frequency with which errors are injected. Replaces xfs_etest; the
* value stored in here is the inverse of the frequency with which the
* error triggers. 1 = always, 2 = half the time, etc.
*/
unsigned int *m_errortag;
struct xfs_kobj m_errortag_kobj;
#endif
} xfs_mount_t;
/*
* Flags for m_flags.
*/
#define XFS_MOUNT_WSYNC (1ULL << 0) /* for nfs - all metadata ops
must be synchronous except
for space allocations */
#define XFS_MOUNT_UNMOUNTING (1ULL << 1) /* filesystem is unmounting */
#define XFS_MOUNT_BAD_SUMMARY (1ULL << 2) /* summary counters are bad */
#define XFS_MOUNT_WAS_CLEAN (1ULL << 3)
#define XFS_MOUNT_FS_SHUTDOWN (1ULL << 4) /* atomic stop of all filesystem
operations, typically for
disk errors in metadata */
#define XFS_MOUNT_DISCARD (1ULL << 5) /* discard unused blocks */
#define XFS_MOUNT_NOALIGN (1ULL << 7) /* turn off stripe alignment
allocations */
#define XFS_MOUNT_ATTR2 (1ULL << 8) /* allow use of attr2 format */
#define XFS_MOUNT_GRPID (1ULL << 9) /* group-ID assigned from directory */
#define XFS_MOUNT_NORECOVERY (1ULL << 10) /* no recovery - dirty fs */
#define XFS_MOUNT_DFLT_IOSIZE (1ULL << 12) /* set default i/o size */
#define XFS_MOUNT_SMALL_INUMS (1ULL << 14) /* user wants 32bit inodes */
#define XFS_MOUNT_32BITINODES (1ULL << 15) /* inode32 allocator active */
#define XFS_MOUNT_NOUUID (1ULL << 16) /* ignore uuid during mount */
#define XFS_MOUNT_IKEEP (1ULL << 18) /* keep empty inode clusters*/
#define XFS_MOUNT_SWALLOC (1ULL << 19) /* turn on stripe width
* allocation */
#define XFS_MOUNT_RDONLY (1ULL << 20) /* read-only fs */
#define XFS_MOUNT_DIRSYNC (1ULL << 21) /* synchronous directory ops */
#define XFS_MOUNT_COMPAT_IOSIZE (1ULL << 22) /* don't report large preferred
* I/O size in stat() */
#define XFS_MOUNT_FILESTREAMS (1ULL << 24) /* enable the filestreams
allocator */
#define XFS_MOUNT_NOATTR2 (1ULL << 25) /* disable use of attr2 format */
#define XFS_MOUNT_DAX (1ULL << 62) /* TEST ONLY! */
/*
* Default minimum read and write sizes.
*/
#define XFS_READIO_LOG_LARGE 16
#define XFS_WRITEIO_LOG_LARGE 16
/*
* Max and min values for mount-option defined I/O
* preallocation sizes.
*/
#define XFS_MAX_IO_LOG 30 /* 1G */
#define XFS_MIN_IO_LOG PAGE_SHIFT
/*
* Synchronous read and write sizes. This should be
* better for NFSv2 wsync filesystems.
*/
#define XFS_WSYNC_READIO_LOG 15 /* 32k */
#define XFS_WSYNC_WRITEIO_LOG 14 /* 16k */
/*
* Allow large block sizes to be reported to userspace programs if the
* "largeio" mount option is used.
*
* If compatibility mode is specified, simply return the basic unit of caching
* so that we don't get inefficient read/modify/write I/O from user apps.
* Otherwise....
*
* If the underlying volume is a stripe, then return the stripe width in bytes
* as the recommended I/O size. It is not a stripe and we've set a default
* buffered I/O size, return that, otherwise return the compat default.
*/
static inline unsigned long
xfs_preferred_iosize(xfs_mount_t *mp)
{
if (mp->m_flags & XFS_MOUNT_COMPAT_IOSIZE)
return PAGE_SIZE;
return (mp->m_swidth ?
(mp->m_swidth << mp->m_sb.sb_blocklog) :
((mp->m_flags & XFS_MOUNT_DFLT_IOSIZE) ?
(1 << (int)max(mp->m_readio_log, mp->m_writeio_log)) :
PAGE_SIZE));
}
#define XFS_LAST_UNMOUNT_WAS_CLEAN(mp) \
((mp)->m_flags & XFS_MOUNT_WAS_CLEAN)
#define XFS_FORCED_SHUTDOWN(mp) ((mp)->m_flags & XFS_MOUNT_FS_SHUTDOWN)
void xfs_do_force_shutdown(struct xfs_mount *mp, int flags, char *fname,
int lnnum);
#define xfs_force_shutdown(m,f) \
xfs_do_force_shutdown(m, f, __FILE__, __LINE__)
#define SHUTDOWN_META_IO_ERROR 0x0001 /* write attempt to metadata failed */
#define SHUTDOWN_LOG_IO_ERROR 0x0002 /* write attempt to the log failed */
#define SHUTDOWN_FORCE_UMOUNT 0x0004 /* shutdown from a forced unmount */
#define SHUTDOWN_CORRUPT_INCORE 0x0008 /* corrupt in-memory data structures */
#define SHUTDOWN_REMOTE_REQ 0x0010 /* shutdown came from remote cell */
#define SHUTDOWN_DEVICE_REQ 0x0020 /* failed all paths to the device */
/*
* Flags for xfs_mountfs
*/
#define XFS_MFSI_QUIET 0x40 /* Be silent if mount errors found */
static inline xfs_agnumber_t
xfs_daddr_to_agno(struct xfs_mount *mp, xfs_daddr_t d)
{
xfs_rfsblock_t ld = XFS_BB_TO_FSBT(mp, d);
do_div(ld, mp->m_sb.sb_agblocks);
return (xfs_agnumber_t) ld;
}
static inline xfs_agblock_t
xfs_daddr_to_agbno(struct xfs_mount *mp, xfs_daddr_t d)
{
xfs_rfsblock_t ld = XFS_BB_TO_FSBT(mp, d);
return (xfs_agblock_t) do_div(ld, mp->m_sb.sb_agblocks);
}
/* per-AG block reservation data structures*/
enum xfs_ag_resv_type {
XFS_AG_RESV_NONE = 0,
XFS_AG_RESV_AGFL,
XFS_AG_RESV_METADATA,
XFS_AG_RESV_RMAPBT,
};
struct xfs_ag_resv {
/* number of blocks originally reserved here */
xfs_extlen_t ar_orig_reserved;
/* number of blocks reserved here */
xfs_extlen_t ar_reserved;
/* number of blocks originally asked for */
xfs_extlen_t ar_asked;
};
/*
* Per-ag incore structure, copies of information in agf and agi, to improve the
* performance of allocation group selection.
*/
typedef struct xfs_perag {
struct xfs_mount *pag_mount; /* owner filesystem */
xfs_agnumber_t pag_agno; /* AG this structure belongs to */
atomic_t pag_ref; /* perag reference count */
char pagf_init; /* this agf's entry is initialized */
char pagi_init; /* this agi's entry is initialized */
char pagf_metadata; /* the agf is preferred to be metadata */
char pagi_inodeok; /* The agi is ok for inodes */
uint8_t pagf_levels[XFS_BTNUM_AGF];
/* # of levels in bno & cnt btree */
bool pagf_agflreset; /* agfl requires reset before use */
uint32_t pagf_flcount; /* count of blocks in freelist */
xfs_extlen_t pagf_freeblks; /* total free blocks */
xfs_extlen_t pagf_longest; /* longest free space */
uint32_t pagf_btreeblks; /* # of blocks held in AGF btrees */
xfs_agino_t pagi_freecount; /* number of free inodes */
xfs_agino_t pagi_count; /* number of allocated inodes */
/*
* Inode allocation search lookup optimisation.
* If the pagino matches, the search for new inodes
* doesn't need to search the near ones again straight away
*/
xfs_agino_t pagl_pagino;
xfs_agino_t pagl_leftrec;
xfs_agino_t pagl_rightrec;
spinlock_t pagb_lock; /* lock for pagb_tree */
struct rb_root pagb_tree; /* ordered tree of busy extents */
unsigned int pagb_gen; /* generation count for pagb_tree */
wait_queue_head_t pagb_wait; /* woken when pagb_gen changes */
atomic_t pagf_fstrms; /* # of filestreams active in this AG */
spinlock_t pag_ici_lock; /* incore inode cache lock */
struct radix_tree_root pag_ici_root; /* incore inode cache root */
int pag_ici_reclaimable; /* reclaimable inodes */
struct mutex pag_ici_reclaim_lock; /* serialisation point */
unsigned long pag_ici_reclaim_cursor; /* reclaim restart point */
/* buffer cache index */
spinlock_t pag_buf_lock; /* lock for pag_buf_hash */
struct rhashtable pag_buf_hash;
/* for rcu-safe freeing */
struct rcu_head rcu_head;
int pagb_count; /* pagb slots in use */
/* Blocks reserved for all kinds of metadata. */
struct xfs_ag_resv pag_meta_resv;
/* Blocks reserved for the reverse mapping btree. */
struct xfs_ag_resv pag_rmapbt_resv;
/* reference count */
uint8_t pagf_refcount_level;
/*
* Unlinked inode information. This incore information reflects
* data stored in the AGI, so callers must hold the AGI buffer lock
* or have some other means to control concurrency.
*/
struct rhashtable pagi_unlinked_hash;
} xfs_perag_t;
static inline struct xfs_ag_resv *
xfs_perag_resv(
struct xfs_perag *pag,
enum xfs_ag_resv_type type)
{
switch (type) {
case XFS_AG_RESV_METADATA:
return &pag->pag_meta_resv;
case XFS_AG_RESV_RMAPBT:
return &pag->pag_rmapbt_resv;
default:
return NULL;
}
}
int xfs_buf_hash_init(xfs_perag_t *pag);
void xfs_buf_hash_destroy(xfs_perag_t *pag);
extern void xfs_uuid_table_free(void);
extern int xfs_log_sbcount(xfs_mount_t *);
extern uint64_t xfs_default_resblks(xfs_mount_t *mp);
extern int xfs_mountfs(xfs_mount_t *mp);
extern int xfs_initialize_perag(xfs_mount_t *mp, xfs_agnumber_t agcount,
xfs_agnumber_t *maxagi);
extern void xfs_unmountfs(xfs_mount_t *);
extern int xfs_mod_icount(struct xfs_mount *mp, int64_t delta);
extern int xfs_mod_ifree(struct xfs_mount *mp, int64_t delta);
extern int xfs_mod_fdblocks(struct xfs_mount *mp, int64_t delta,
bool reserved);
extern int xfs_mod_frextents(struct xfs_mount *mp, int64_t delta);
extern struct xfs_buf *xfs_getsb(xfs_mount_t *, int);
extern int xfs_readsb(xfs_mount_t *, int);
extern void xfs_freesb(xfs_mount_t *);
extern bool xfs_fs_writable(struct xfs_mount *mp, int level);
extern int xfs_sb_validate_fsb_count(struct xfs_sb *, uint64_t);
extern int xfs_dev_is_read_only(struct xfs_mount *, char *);
extern void xfs_set_low_space_thresholds(struct xfs_mount *);
int xfs_zero_extent(struct xfs_inode *ip, xfs_fsblock_t start_fsb,
xfs_off_t count_fsb);
struct xfs_error_cfg * xfs_error_get_cfg(struct xfs_mount *mp,
int error_class, int error);
void xfs_force_summary_recalc(struct xfs_mount *mp);
#endif /* __XFS_MOUNT_H__ */
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