[PATCH v2 47/47] xfs: introduce the XFS_IOC_GETFSMAP ioctl

Darrick J. Wong
2016-07-23T04:28:38Z

Introduce a new ioctl that uses the reverse mapping btree to return
information about the physical layout of the filesystem.

v2: shorten the device field to u32 since that's all we need for
dev_t. Support reporting reverse mapping information for all the
devices that XFS supports (data, log).

v3: don't call the function that reports the journalling log rmap if
we don't have an external device, since the regular rmapbt will take
care of that.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
---
fs/xfs/libxfs/xfs_fs.h | 65 ++++++
fs/xfs/xfs_fsops.c | 528 ++++++++++++++++++++++++++++++++++++++++++++++++
fs/xfs/xfs_fsops.h | 6 +
fs/xfs/xfs_ioctl.c | 76 +++++++
fs/xfs/xfs_ioctl32.c | 1
fs/xfs/xfs_trace.h | 76 +++++++
6 files changed, 752 insertions(+)

diff --git a/fs/xfs/libxfs/xfs_fs.h b/fs/xfs/libxfs/xfs_fs.h
index 7945505..b08f23d 100644
--- a/fs/xfs/libxfs/xfs_fs.h
+++ b/fs/xfs/libxfs/xfs_fs.h
@@ -91,6 +91,70 @@ struct getbmapx {
#define BMV_OF_LAST 0x4 /* segment is the last in the file */

/*
+ * Structure for XFS_IOC_GETFSMAP.
+ *
+ * Similar to XFS_IOC_GETBMAPX, the first two elements in the array are
+ * used to constrain the output. The first element in the array should
+ * represent the lowest disk address that the user wants to learn about.
+ * The second element in the array should represent the highest disk
+ * address to query. Subsequent array elements will be filled out by the
+ * command.
+ *
+ * The fmv_iflags field is only used in the first structure. The
+ * fmv_oflags field is filled in for each returned structure after the
+ * second structure. The fmv_unused1 fields in the first two array
+ * elements must be zero.
+ *
+ * The fmv_count, fmv_entries, and fmv_iflags fields in the second array
+ * element must be zero.
+ *
+ * fmv_block, fmv_offset, and fmv_length are expressed in units of 512
+ * byte sectors.
+ */
+#ifndef HAVE_GETFSMAP
+struct getfsmap {
+ __u32 fmv_device; /* device id */
+ __u32 fmv_unused1; /* future use, must be zero */
+ __u64 fmv_block; /* starting block */
+ __u64 fmv_owner; /* owner id */
+ __u64 fmv_offset; /* file offset of segment */
+ __u64 fmv_length; /* length of segment, blocks */
+ __u32 fmv_oflags; /* mapping flags */
+ __u32 fmv_iflags; /* control flags (1st structure) */
+ __u32 fmv_count; /* # of entries in array incl. input */
+ __u32 fmv_entries; /* # of entries filled in (output). */
+ __u64 fmv_unused2; /* future use, must be zero */
+};
+#endif
+
+/* fmv_iflags values - set by XFS_IOC_GETFSMAP caller in the header. */
+/* no flags defined yet */
+#define FMV_HIF_VALID 0
+
+/* fmv_oflags values - returned in the header segment only. */
+#define FMV_HOF_DEV_T 0x1 /* fmv_device values will be dev_t */
+
+/* fmv_flags values - returned for each non-header segment */
+#define FMV_OF_PREALLOC 0x1 /* segment = unwritten pre-allocation */
+#define FMV_OF_ATTR_FORK 0x2 /* segment = attribute fork */
+#define FMV_OF_EXTENT_MAP 0x4 /* segment = extent map */
+#define FMV_OF_SHARED 0x8 /* segment = shared with another file */
+#define FMV_OF_SPECIAL_OWNER 0x10 /* owner is a special value */
+#define FMV_OF_LAST 0x20 /* segment is the last in the FS */
+
+/* fmv_owner special values */
+#define FMV_OWN_FREE (-1ULL) /* free space */
+#define FMV_OWN_UNKNOWN (-2ULL) /* unknown owner */
+#define FMV_OWN_FS (-3ULL) /* static fs metadata */
+#define FMV_OWN_LOG (-4ULL) /* journalling log */
+#define FMV_OWN_AG (-5ULL) /* per-AG metadata */
+#define FMV_OWN_INOBT (-6ULL) /* inode btree blocks */
+#define FMV_OWN_INODES (-7ULL) /* inodes */
+#define FMV_OWN_REFC (-8ULL) /* refcount tree */
+#define FMV_OWN_COW (-9ULL) /* cow staging */
+#define FMV_OWN_DEFECTIVE (-10ULL) /* bad blocks */
+
+/*
* Structure for XFS_IOC_FSSETDM.
* For use by backup and restore programs to set the XFS on-disk inode
* fields di_dmevmask and di_dmstate. These must be set to exactly and
@@ -498,6 +562,7 @@ typedef struct xfs_swapext
#define XFS_IOC_GETBMAPX _IOWR('X', 56, struct getbmap)
#define XFS_IOC_ZERO_RANGE _IOW ('X', 57, struct xfs_flock64)
#define XFS_IOC_FREE_EOFBLOCKS _IOR ('X', 58, struct xfs_fs_eofblocks)
+#define XFS_IOC_GETFSMAP _IOWR('X', 59, struct getfsmap)

/*
* ioctl commands that replace IRIX syssgi()'s
diff --git a/fs/xfs/xfs_fsops.c b/fs/xfs/xfs_fsops.c
index 0f96847..39a4231 100644
--- a/fs/xfs/xfs_fsops.c
+++ b/fs/xfs/xfs_fsops.c
@@ -43,6 +43,7 @@
#include "xfs_log.h"
#include "xfs_filestream.h"
#include "xfs_rmap.h"
+#include "xfs_bit.h"

/*
* File system operations
@@ -947,3 +948,530 @@ xfs_do_force_shutdown(
"Please umount the filesystem and rectify the problem(s)");
}
}
+
+/* getfsmap query state */
+struct xfs_getfsmap_info {
+ struct getfsmap *fmv; /* vector header */
+ xfs_fsmap_format_t formatter; /* formatting fn */
+ void *format_arg; /* format buffer */
+ bool last; /* last extent? */
+ xfs_daddr_t next_daddr; /* next daddr we expect */
+ u32 dev; /* device id */
+
+ xfs_agnumber_t agno; /* AG number, if applicable */
+ struct xfs_buf *agbp; /* AGF, for refcount queries */
+ struct xfs_rmap_irec low; /* low rmap key */
+ struct xfs_rmap_irec high; /* high rmap key */
+};
+
+/* Associate a device with a getfsmap handler. */
+struct xfs_getfsmap_dev {
+ u32 dev;
+ int (*fn)(struct xfs_mount *mp,
+ struct getfsmap *keys,
+ struct xfs_getfsmap_info *info);
+};
+
+/* Compare two getfsmap device handlers. */
+static int
+xfs_getfsmap_dev_compare(
+ const void *p1,
+ const void *p2)
+{
+ const struct xfs_getfsmap_dev *d1 = p1;
+ const struct xfs_getfsmap_dev *d2 = p2;
+
+ return d1->dev - d2->dev;
+}
+
+/* Compare a record against our starting point */
+static bool
+xfs_getfsmap_rec_before_low_key(
+ struct xfs_getfsmap_info *info,
+ struct xfs_rmap_irec *rec)
+{
+ uint64_t x, y;
+
+ if (rec->rm_startblock < info->low.rm_startblock)
+ return true;
+ if (rec->rm_startblock > info->low.rm_startblock)
+ return false;
+
+ if (rec->rm_owner < info->low.rm_owner)
+ return true;
+ if (rec->rm_owner > info->low.rm_owner)
+ return false;
+
+ x = xfs_rmap_irec_offset_pack(rec);
+ y = xfs_rmap_irec_offset_pack(&info->low);
+ if (x < y)
+ return true;
+ return false;
+}
+
+/*
+ * Format a reverse mapping for getfsmap, having translated rm_startblock
+ * into the appropriate daddr units.
+ */
+STATIC int
+xfs_getfsmap_helper(
+ struct xfs_mount *mp,
+ struct xfs_getfsmap_info *info,
+ struct xfs_rmap_irec *rec,
+ xfs_daddr_t rec_daddr)
+{
+ struct getfsmap fmv;
+ xfs_daddr_t key_end;
+ int error;
+
+ /*
+ * Filter out records that start before our startpoint, if the
+ * caller requested that.
+ */
+ if (info->fmv->fmv_length &&
+ xfs_getfsmap_rec_before_low_key(info, rec)) {
+ rec_daddr += XFS_FSB_TO_BB(mp, rec->rm_blockcount);
+ if (info->next_daddr < rec_daddr)
+ info->next_daddr = rec_daddr;
+ return XFS_BTREE_QUERY_RANGE_CONTINUE;
+ }
+
+ /*
+ * If the caller passed in a length with the low record and
+ * the record represents a file data extent, we incremented
+ * the offset in the low key by the length in the hopes of
+ * finding reverse mappings for the physical blocks we just
+ * saw. We did /not/ increment next_daddr by the length
+ * because the range query would not be able to find shared
+ * extents within the same physical block range.
+ *
+ * However, the extent we've been fed could have a startblock
+ * past the passed-in low record. If this is the case,
+ * advance next_daddr to the end of the passed-in low record
+ * so we don't report the extent prior to this extent as
+ * free.
+ */
+ key_end = info->fmv->fmv_block + info->fmv->fmv_length;
+ if (info->next_daddr < key_end && rec_daddr >= key_end)
+ info->next_daddr = key_end;
+
+ /* Are we just counting mappings? */
+ if (info->fmv->fmv_count == 2) {
+ if (rec_daddr > info->next_daddr)
+ info->fmv->fmv_entries++;
+
+ if (info->last)
+ return XFS_BTREE_QUERY_RANGE_CONTINUE;
+
+ info->fmv->fmv_entries++;
+
+ rec_daddr += XFS_FSB_TO_BB(mp, rec->rm_blockcount);
+ if (info->next_daddr < rec_daddr)
+ info->next_daddr = rec_daddr;
+ return XFS_BTREE_QUERY_RANGE_CONTINUE;
+ }
+
+ /*
+ * If the record starts past the last physical block we saw,
+ * then we've found some free space. Report that too.
+ */
+ if (rec_daddr > info->next_daddr) {
+ if (info->fmv->fmv_entries >= info->fmv->fmv_count - 2)
+ return XFS_BTREE_QUERY_RANGE_ABORT;
+
+ trace_xfs_fsmap_mapping(mp, info->agno,
+ XFS_DADDR_TO_FSB(mp, info->next_daddr),
+ XFS_DADDR_TO_FSB(mp, rec_daddr -
+ info->next_daddr),
+ FMV_OWN_FREE, 0);
+
+ fmv.fmv_device = info->dev;
+ fmv.fmv_block = info->next_daddr;
+ fmv.fmv_owner = FMV_OWN_FREE;
+ fmv.fmv_offset = 0;
+ fmv.fmv_length = rec_daddr - info->next_daddr;
+ fmv.fmv_oflags = FMV_OF_SPECIAL_OWNER;
+ fmv.fmv_count = 0;
+ fmv.fmv_entries = 0;
+ fmv.fmv_unused1 = 0;
+ fmv.fmv_unused2 = 0;
+ error = info->formatter(&fmv, info->format_arg);
+ if (error)
+ return error;
+ info->fmv->fmv_entries++;
+ }
+
+ if (info->last)
+ goto out;
+
+ /* Fill out the extent we found */
+ if (info->fmv->fmv_entries >= info->fmv->fmv_count - 2)
+ return XFS_BTREE_QUERY_RANGE_ABORT;
+
+ trace_xfs_fsmap_mapping(mp, info->agno,
+ rec->rm_startblock, rec->rm_blockcount, rec->rm_owner,
+ rec->rm_offset);
+
+ fmv.fmv_device = info->dev;
+ fmv.fmv_block = rec_daddr;
+ fmv.fmv_owner = rec->rm_owner;
+ fmv.fmv_offset = XFS_FSB_TO_BB(mp, rec->rm_offset);
+ fmv.fmv_length = XFS_FSB_TO_BB(mp, rec->rm_blockcount);
+ fmv.fmv_oflags = 0;
+ fmv.fmv_count = 0;
+ fmv.fmv_entries = 0;
+ fmv.fmv_unused1 = 0;
+ fmv.fmv_unused2 = 0;
+ if (XFS_RMAP_NON_INODE_OWNER(rec->rm_owner))
+ fmv.fmv_oflags |= FMV_OF_SPECIAL_OWNER;
+ if (rec->rm_flags & XFS_RMAP_UNWRITTEN)
+ fmv.fmv_oflags |= FMV_OF_PREALLOC;
+ if (rec->rm_flags & XFS_RMAP_ATTR_FORK)
+ fmv.fmv_oflags |= FMV_OF_ATTR_FORK;
+ if (rec->rm_flags & XFS_RMAP_BMBT_BLOCK)
+ fmv.fmv_oflags |= FMV_OF_EXTENT_MAP;
+ error = info->formatter(&fmv, info->format_arg);
+ if (error)
+ return error;
+ info->fmv->fmv_entries++;
+
+out:
+ rec_daddr += XFS_FSB_TO_BB(mp, rec->rm_blockcount);
+ if (info->next_daddr < rec_daddr)
+ info->next_daddr = rec_daddr;
+ return XFS_BTREE_QUERY_RANGE_CONTINUE;
+}
+
+/* Transform a rmapbt irec into a fsmap */
+STATIC int
+xfs_getfsmap_datadev_helper(
+ struct xfs_btree_cur *cur,
+ struct xfs_rmap_irec *rec,
+ void *priv)
+{
+ struct xfs_mount *mp = cur->bc_mp;
+ struct xfs_getfsmap_info *info = priv;
+ xfs_fsblock_t fsb;
+ xfs_daddr_t rec_daddr;
+
+ fsb = XFS_AGB_TO_FSB(mp, cur->bc_private.a.agno,
+ rec->rm_startblock);
+ rec_daddr = XFS_FSB_TO_DADDR(mp, fsb);
+
+ return xfs_getfsmap_helper(mp, info, rec, rec_daddr);
+}
+
+/* Transform a absolute-startblock rmap (rtdev, logdev) into a fsmap */
+STATIC int
+xfs_getfsmap_rtdev_helper(
+ struct xfs_btree_cur *cur,
+ struct xfs_rmap_irec *rec,
+ void *priv)
+{
+ struct xfs_mount *mp = cur->bc_mp;
+ struct xfs_getfsmap_info *info = priv;
+ xfs_daddr_t rec_daddr;
+
+ rec_daddr = XFS_FSB_TO_BB(mp, rec->rm_startblock);
+
+ return xfs_getfsmap_helper(mp, info, rec, rec_daddr);
+}
+
+/* Set rmap flags based on the getfsmap flags */
+static void
+xfs_getfsmap_set_irec_flags(
+ struct xfs_rmap_irec *irec,
+ struct getfsmap *fmv)
+{
+ irec->rm_flags = 0;
+ if (fmv->fmv_oflags & FMV_OF_ATTR_FORK)
+ irec->rm_flags |= XFS_RMAP_ATTR_FORK;
+ if (fmv->fmv_oflags & FMV_OF_EXTENT_MAP)
+ irec->rm_flags |= XFS_RMAP_BMBT_BLOCK;
+ if (fmv->fmv_oflags & FMV_OF_PREALLOC)
+ irec->rm_flags |= XFS_RMAP_UNWRITTEN;
+}
+
+/* Execute a getfsmap query against the log device. */
+STATIC int
+xfs_getfsmap_logdev(
+ struct xfs_mount *mp,
+ struct getfsmap *keys,
+ struct xfs_getfsmap_info *info)
+{
+ struct xfs_btree_cur cur;
+ struct getfsmap *lowkey = keys;
+ struct xfs_rmap_irec rmap;
+
+ /* Set up search keys */
+ info->low.rm_startblock = XFS_BB_TO_FSBT(mp, lowkey->fmv_block);
+ info->low.rm_offset = XFS_BB_TO_FSBT(mp, lowkey->fmv_offset);
+ info->low.rm_owner = lowkey->fmv_owner;
+ info->low.rm_blockcount = 0;
+ xfs_getfsmap_set_irec_flags(&info->low, lowkey);
+
+ info->high.rm_startblock = -1U;
+ info->high.rm_owner = ULLONG_MAX;
+ info->high.rm_offset = ULLONG_MAX;
+ info->high.rm_blockcount = 0;
+ info->high.rm_flags = XFS_RMAP_KEY_FLAGS | XFS_RMAP_REC_FLAGS;
+
+ trace_xfs_fsmap_low_key(mp, info->agno,
+ info->low.rm_startblock,
+ info->low.rm_blockcount,
+ info->low.rm_owner,
+ info->low.rm_offset);
+
+ trace_xfs_fsmap_high_key(mp, info->agno,
+ info->high.rm_startblock,
+ info->high.rm_blockcount,
+ info->high.rm_owner,
+ info->high.rm_offset);
+
+
+ if (lowkey->fmv_block > 0)
+ return 0;
+
+ rmap.rm_startblock = 0;
+ rmap.rm_blockcount = mp->m_sb.sb_logblocks;
+ rmap.rm_owner = XFS_RMAP_OWN_LOG;
+ rmap.rm_offset = 0;
+ rmap.rm_flags = 0;
+
+ cur.bc_mp = mp;
+ return xfs_getfsmap_rtdev_helper(&cur, &rmap, info);
+}
+
+/* Execute a getfsmap query against the regular data device. */
+STATIC int
+xfs_getfsmap_datadev(
+ struct xfs_mount *mp,
+ struct getfsmap *keys,
+ struct xfs_getfsmap_info *info)
+{
+ struct xfs_btree_cur *bt_cur = NULL;
+ struct getfsmap *lowkey;
+ struct getfsmap *highkey;
+ xfs_fsblock_t start_fsb;
+ xfs_fsblock_t end_fsb;
+ xfs_agnumber_t start_ag;
+ xfs_agnumber_t end_ag;
+ xfs_daddr_t eofs;
+ int error = 0;
+
+ lowkey = keys;
+ highkey = keys + 1;
+ eofs = XFS_FSB_TO_BB(mp, mp->m_sb.sb_dblocks);
+ if (lowkey->fmv_block >= eofs)
+ return 0;
+ if (highkey->fmv_block >= eofs)
+ highkey->fmv_block = eofs - 1;
+ start_fsb = XFS_DADDR_TO_FSB(mp, lowkey->fmv_block);
+ end_fsb = XFS_DADDR_TO_FSB(mp, highkey->fmv_block);
+
+ /* Set up search keys */
+ info->low.rm_startblock = XFS_FSB_TO_AGBNO(mp, start_fsb);
+ info->low.rm_offset = XFS_BB_TO_FSBT(mp, lowkey->fmv_offset);
+ info->low.rm_owner = lowkey->fmv_owner;
+ info->low.rm_blockcount = 0;
+ xfs_getfsmap_set_irec_flags(&info->low, lowkey);
+
+ info->high.rm_startblock = -1U;
+ info->high.rm_owner = ULLONG_MAX;
+ info->high.rm_offset = ULLONG_MAX;
+ info->high.rm_blockcount = 0;
+ info->high.rm_flags = XFS_RMAP_KEY_FLAGS | XFS_RMAP_REC_FLAGS;
+
+ start_ag = XFS_FSB_TO_AGNO(mp, start_fsb);
+ end_ag = XFS_FSB_TO_AGNO(mp, end_fsb);
+
+ /* Query each AG */
+ for (info->agno = start_ag; info->agno <= end_ag; info->agno++) {
+ if (info->agno == end_ag) {
+ info->high.rm_startblock = XFS_FSB_TO_AGBNO(mp,
+ end_fsb);
+ info->high.rm_offset = XFS_BB_TO_FSBT(mp,
+ highkey->fmv_offset);
+ info->high.rm_owner = highkey->fmv_owner;
+ xfs_getfsmap_set_irec_flags(&info->high, highkey);
+ }
+
+ if (bt_cur) {
+ xfs_btree_del_cursor(bt_cur, XFS_BTREE_NOERROR);
+ xfs_trans_brelse(NULL, info->agbp);
+ bt_cur = NULL;
+ info->agbp = NULL;
+ }
+
+ error = xfs_alloc_read_agf(mp, NULL, info->agno, 0,
+ &info->agbp);
+ if (error)
+ goto err;
+
+ trace_xfs_fsmap_low_key(mp, info->agno,
+ info->low.rm_startblock,
+ info->low.rm_blockcount,
+ info->low.rm_owner,
+ info->low.rm_offset);
+
+ trace_xfs_fsmap_high_key(mp, info->agno,
+ info->high.rm_startblock,
+ info->high.rm_blockcount,
+ info->high.rm_owner,
+ info->high.rm_offset);
+
+ bt_cur = xfs_rmapbt_init_cursor(mp, NULL, info->agbp,
+ info->agno);
+ error = xfs_rmap_query_range(bt_cur, &info->low, &info->high,
+ xfs_getfsmap_datadev_helper, info);
+ if (error)
+ goto err;
+
+ if (info->agno == start_ag) {
+ info->low.rm_startblock = 0;
+ info->low.rm_owner = 0;
+ info->low.rm_offset = 0;
+ info->low.rm_flags = 0;
+ }
+ }
+
+ /* Report any free space at the end of the AG */
+ info->last = true;
+ error = xfs_getfsmap_datadev_helper(bt_cur, &info->high, info);
+ if (error)
+ goto err;
+
+err:
+ if (bt_cur)
+ xfs_btree_del_cursor(bt_cur, error < 0 ? XFS_BTREE_ERROR :
+ XFS_BTREE_NOERROR);
+ if (info->agbp) {
+ xfs_trans_brelse(NULL, info->agbp);
+ info->agbp = NULL;
+ }
+
+ return error;
+}
+
+/* Do we recognize the device? */
+STATIC bool
+xfs_getfsmap_is_valid_device(
+ struct xfs_mount *mp,
+ struct getfsmap *fmv)
+{
+ if (fmv->fmv_device == 0 || fmv->fmv_device == UINT_MAX ||
+ fmv->fmv_device == new_encode_dev(mp->m_ddev_targp->bt_dev))
+ return true;
+ if (mp->m_logdev_targp &&
+ fmv->fmv_device == new_encode_dev(mp->m_logdev_targp->bt_dev))
+ return true;
+ return false;
+}
+
+#define XFS_GETFSMAP_DEVS 3
+/*
+ * Get filesystem's extents as described in fmv, and format for
+ * output. Calls formatter to fill the user's buffer until all
+ * extents are mapped, until the passed-in fmv->fmv_count slots have
+ * been filled, or until the formatter short-circuits the loop, if it
+ * is tracking filled-in extents on its own.
+ */
+int
+xfs_getfsmap(
+ struct xfs_mount *mp,
+ struct getfsmap *fmv_low,
+ xfs_fsmap_format_t formatter,
+ void *arg)
+{
+ struct getfsmap *fmv_high;
+ struct getfsmap keys[2];
+ struct xfs_getfsmap_dev handlers[XFS_GETFSMAP_DEVS];
+ struct xfs_getfsmap_info info;
+ int i;
+ int error = 0;
+
+ if (!xfs_sb_version_hasrmapbt(&mp->m_sb))
+ return -EOPNOTSUPP;
+ if (fmv_low->fmv_count < 2)
+ return -EINVAL;
+ if (fmv_low->fmv_iflags & (~FMV_HIF_VALID))
+ return -EINVAL;
+ fmv_high = fmv_low + 1;
+ if (!xfs_getfsmap_is_valid_device(mp, fmv_low) ||
+ !xfs_getfsmap_is_valid_device(mp, fmv_high) ||
+ fmv_high->fmv_iflags || fmv_high->fmv_count ||
+ fmv_high->fmv_length || fmv_high->fmv_entries ||
+ fmv_high->fmv_unused1 || fmv_low->fmv_unused1 ||
+ fmv_high->fmv_unused2 || fmv_low->fmv_unused2)
+ return -EINVAL;
+
+ fmv_low->fmv_entries = 0;
+
+ /* Set up our device handlers. */
+ memset(handlers, 0, sizeof(handlers));
+ handlers[0].dev = new_encode_dev(mp->m_ddev_targp->bt_dev);
+ handlers[0].fn = xfs_getfsmap_datadev;
+ if (mp->m_logdev_targp != mp->m_ddev_targp) {
+ handlers[1].dev = new_encode_dev(mp->m_logdev_targp->bt_dev);
+ handlers[1].fn = xfs_getfsmap_logdev;
+ }
+
+ xfs_sort(handlers, XFS_GETFSMAP_DEVS, sizeof(struct xfs_getfsmap_dev),
+ xfs_getfsmap_dev_compare);
+
+ /*
+ * Since we allow the user to copy the last fmv item from a previous
+ * call into the low key slot, we have to advance the low key by
+ * whatever the reported length is. If the offset field doesn't apply,
+ * move up the start block to the next extent and start over with the
+ * lowest owner/offset possible; otherwise it's file data, so move up
+ * the offset only.
+ */
+ keys[0] = *fmv_low;
+ if (keys[0].fmv_oflags & (FMV_OF_SPECIAL_OWNER | FMV_OF_EXTENT_MAP)) {
+ keys[0].fmv_block += fmv_low->fmv_length;
+ keys[0].fmv_owner = 0;
+ keys[0].fmv_offset = 0;
+ } else
+ keys[0].fmv_offset += fmv_low->fmv_length;
+ memset(keys + 1, 0xFF, sizeof(struct getfsmap));
+
+ info.fmv = fmv_low;
+ info.formatter = formatter;
+ info.format_arg = arg;
+
+ /* For each device we support... */
+ for (i = 0; i < XFS_GETFSMAP_DEVS; i++) {
+ /* Is this device within the range the user asked for? */
+ if (!handlers[i].fn)
+ continue;
+ if (fmv_low->fmv_device > handlers[i].dev)
+ continue;
+ if (fmv_high->fmv_device < handlers[i].dev)
+ break;
+
+ /*
+ * If this device number matches the high key, we have
+ * to pass the high key to the handler to limit the
+ * query results. If the device number exceeds the
+ * low key, zero out the low key so that we get
+ * everything from the beginning.
+ */
+ if (handlers[i].dev == fmv_high->fmv_device)
+ keys[1] = *fmv_high;
+ if (handlers[i].dev > fmv_low->fmv_device)
+ memset(keys, 0, sizeof(struct getfsmap));
+
+ info.next_daddr = keys[0].fmv_block;
+ info.dev = handlers[i].dev;
+ info.last = false;
+ info.agno = NULLAGNUMBER;
+ error = handlers[i].fn(mp, keys, &info);
+ if (error)
+ break;
+
+ }
+
+ fmv_low->fmv_oflags = FMV_HOF_DEV_T;
+ return error;
+}
diff --git a/fs/xfs/xfs_fsops.h b/fs/xfs/xfs_fsops.h
index f32713f..53ab2d7 100644
--- a/fs/xfs/xfs_fsops.h
+++ b/fs/xfs/xfs_fsops.h
@@ -26,4 +26,10 @@ extern int xfs_reserve_blocks(xfs_mount_t *mp, __uint64_t *inval,
xfs_fsop_resblks_t *outval);
extern int xfs_fs_goingdown(xfs_mount_t *mp, __uint32_t inflags);

+/* fsmap to userspace formatter - copy to user & advance pointer */
+typedef int (*xfs_fsmap_format_t)(struct getfsmap *, void *);
+
+int xfs_getfsmap(struct xfs_mount *mp, struct getfsmap *fmv,
+ xfs_fsmap_format_t formatter, void *arg);
+
#endif /* __XFS_FSOPS_H__ */
diff --git a/fs/xfs/xfs_ioctl.c b/fs/xfs/xfs_ioctl.c
index 9a7c878..ecdd77b 100644
--- a/fs/xfs/xfs_ioctl.c
+++ b/fs/xfs/xfs_ioctl.c
@@ -41,6 +41,7 @@
#include "xfs_trans.h"
#include "xfs_pnfs.h"
#include "xfs_acl.h"
+#include "xfs_btree.h"

#include <linux/capability.h>
#include <linux/dcache.h>
@@ -1532,6 +1533,76 @@ xfs_ioc_getbmapx(
return 0;
}

+struct getfsmap_info {
+ struct xfs_mount *mp;
+ struct getfsmap __user *data;
+ __s64 last_flags;
+};
+
+STATIC int
+xfs_getfsmap_format(struct getfsmap *fmv, void *priv)
+{
+ struct getfsmap_info *info = priv;
+
+ trace_xfs_getfsmap_mapping(info->mp, fmv->fmv_block,
+ fmv->fmv_length, fmv->fmv_owner,
+ fmv->fmv_offset, fmv->fmv_oflags);
+
+ info->last_flags = fmv->fmv_oflags;
+ if (copy_to_user(info->data, fmv, sizeof(struct getfsmap)))
+ return -EFAULT;
+
+ info->data++;
+ return 0;
+}
+
+STATIC int
+xfs_ioc_getfsmap(
+ struct xfs_inode *ip,
+ void __user *arg)
+{
+ struct getfsmap_info info;
+ struct getfsmap fmx[2];
+ bool aborted = false;
+ int error;
+
+ if (copy_from_user(&fmx, arg, 2 * sizeof(struct getfsmap)))
+ return -EFAULT;
+
+ trace_xfs_getfsmap_low_key(ip->i_mount, fmx[0].fmv_block,
+ fmx[0].fmv_length, fmx[0].fmv_owner,
+ fmx[0].fmv_offset, fmx[0].fmv_oflags);
+
+ trace_xfs_getfsmap_high_key(ip->i_mount, fmx[1].fmv_block,
+ fmx[1].fmv_length, fmx[1].fmv_owner,
+ fmx[1].fmv_offset, fmx[1].fmv_oflags);
+
+ info.mp = ip->i_mount;
+ info.data = (__force struct getfsmap *)arg + 2;
+ error = xfs_getfsmap(ip->i_mount, fmx, xfs_getfsmap_format, &info);
+ if (error == XFS_BTREE_QUERY_RANGE_ABORT) {
+ error = 0;
+ aborted = true;
+ }
+ if (error)
+ return error;
+
+ /* If we didn't abort, set the "last" flag in the last fmx */
+ if (!aborted && fmx[0].fmv_entries) {
+ info.data--;
+ info.last_flags |= FMV_OF_LAST;
+ if (copy_to_user(&info.data->fmv_oflags, &info.last_flags,
+ sizeof(info.last_flags)))
+ return -EFAULT;
+ }
+
+ /* copy back header */
+ if (copy_to_user(arg, fmx, 2 * sizeof(struct getfsmap)))
+ return -EFAULT;
+
+ return 0;
+}
+
int
xfs_ioc_swapext(
xfs_swapext_t *sxp)
@@ -1712,6 +1783,11 @@ xfs_file_ioctl(
case XFS_IOC_GETBMAPX:
return xfs_ioc_getbmapx(ip, arg);

+ case XFS_IOC_GETFSMAP:
+ if (!capable(CAP_SYS_ADMIN))
+ return -EPERM;
+ return xfs_ioc_getfsmap(ip, arg);
+
case XFS_IOC_FD_TO_HANDLE:
case XFS_IOC_PATH_TO_HANDLE:
case XFS_IOC_PATH_TO_FSHANDLE: {
diff --git a/fs/xfs/xfs_ioctl32.c b/fs/xfs/xfs_ioctl32.c
index 321f577..9491bc8 100644
--- a/fs/xfs/xfs_ioctl32.c
+++ b/fs/xfs/xfs_ioctl32.c
@@ -554,6 +554,7 @@ xfs_file_compat_ioctl(
case XFS_IOC_GOINGDOWN:
case XFS_IOC_ERROR_INJECTION:
case XFS_IOC_ERROR_CLEARALL:
+ case XFS_IOC_GETFSMAP:
return xfs_file_ioctl(filp, cmd, p);
#ifndef BROKEN_X86_ALIGNMENT
/* These are handled fine if no alignment issues */
diff --git a/fs/xfs/xfs_trace.h b/fs/xfs/xfs_trace.h
index 551b7e2..8a42609 100644
--- a/fs/xfs/xfs_trace.h
+++ b/fs/xfs/xfs_trace.h
@@ -2559,6 +2559,82 @@ DEFINE_RMAPBT_EVENT(xfs_rmap_lookup_le_range_result);
DEFINE_RMAPBT_EVENT(xfs_rmap_find_right_neighbor_result);
DEFINE_RMAPBT_EVENT(xfs_rmap_find_left_neighbor_result);

+/* fsmap traces */
+DECLARE_EVENT_CLASS(xfs_fsmap_class,
+ TP_PROTO(struct xfs_mount *mp, xfs_agnumber_t agno, xfs_fsblock_t bno,
+ xfs_filblks_t len, __uint64_t owner, __uint64_t offset),
+ TP_ARGS(mp, agno, bno, len, owner, offset),
+ TP_STRUCT__entry(
+ __field(dev_t, dev)
+ __field(xfs_agnumber_t, agno)
+ __field(xfs_fsblock_t, bno)
+ __field(xfs_filblks_t, len)
+ __field(__uint64_t, owner)
+ __field(__uint64_t, offset)
+ ),
+ TP_fast_assign(
+ __entry->dev = mp->m_super->s_dev;
+ __entry->agno = agno;
+ __entry->bno = bno;
+ __entry->len = len;
+ __entry->owner = owner;
+ __entry->offset = offset;
+ ),
+ TP_printk("dev %d:%d agno %u bno %llu len %llu owner %lld offset 0x%llx\n",
+ MAJOR(__entry->dev), MINOR(__entry->dev),
+ __entry->agno,
+ __entry->bno,
+ __entry->len,
+ __entry->owner,
+ __entry->offset)
+)
+#define DEFINE_FSMAP_EVENT(name) \
+DEFINE_EVENT(xfs_fsmap_class, name, \
+ TP_PROTO(struct xfs_mount *mp, xfs_agnumber_t agno, \
+ xfs_fsblock_t bno, xfs_filblks_t len, __uint64_t owner, \
+ __uint64_t offset), \
+ TP_ARGS(mp, agno, bno, len, owner, offset))
+DEFINE_FSMAP_EVENT(xfs_fsmap_low_key);
+DEFINE_FSMAP_EVENT(xfs_fsmap_high_key);
+DEFINE_FSMAP_EVENT(xfs_fsmap_mapping);
+
+DECLARE_EVENT_CLASS(xfs_getfsmap_class,
+ TP_PROTO(struct xfs_mount *mp, xfs_daddr_t block, xfs_daddr_t len,
+ __uint64_t owner, __uint64_t offset, __uint64_t flags),
+ TP_ARGS(mp, block, len, owner, offset, flags),
+ TP_STRUCT__entry(
+ __field(dev_t, dev)
+ __field(xfs_daddr_t, block)
+ __field(xfs_daddr_t, len)
+ __field(__uint64_t, owner)
+ __field(__uint64_t, offset)
+ __field(__uint64_t, flags)
+ ),
+ TP_fast_assign(
+ __entry->dev = mp->m_super->s_dev;
+ __entry->block = block;
+ __entry->len = len;
+ __entry->owner = owner;
+ __entry->offset = offset;
+ __entry->flags = flags;
+ ),
+ TP_printk("dev %d:%d block %llu len %llu owner %lld offset %llu flags 0x%llx\n",
+ MAJOR(__entry->dev), MINOR(__entry->dev),
+ __entry->block,
+ __entry->len,
+ __entry->owner,
+ __entry->offset,
+ __entry->flags)
+)
+#define DEFINE_GETFSMAP_EVENT(name) \
+DEFINE_EVENT(xfs_getfsmap_class, name, \
+ TP_PROTO(struct xfs_mount *mp, xfs_daddr_t block, xfs_daddr_t len, \
+ __uint64_t owner, __uint64_t offset, __uint64_t flags), \
+ TP_ARGS(mp, block, len, owner, offset, flags))
+DEFINE_GETFSMAP_EVENT(xfs_getfsmap_low_key);
+DEFINE_GETFSMAP_EVENT(xfs_getfsmap_high_key);
+DEFINE_GETFSMAP_EVENT(xfs_getfsmap_mapping);
+
#endif /* _TRACE_XFS_H */

#undef TRACE_INCLUDE_PATH