Introduce a new ioctl that uses the reverse mapping btree to return
information about the physical layout of the filesystem.
Signed-off-by: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
---
libxfs/xfs_fs.h | 62 +++++++++++++++++++++++++++++++++++++++++++++++++
libxfs/xfs_refcount.c | 51 +++++++++++++++++++++++++++++-----------
libxfs/xfs_refcount.h | 4 +++
3 files changed, 103 insertions(+), 14 deletions(-)
diff --git a/libxfs/xfs_fs.h b/libxfs/xfs_fs.h
index df58c1c..236a5a7 100644
--- a/libxfs/xfs_fs.h
+++ b/libxfs/xfs_fs.h
@@ -117,6 +117,67 @@ struct getbmapx {
#define BMV_OF_SHARED 0x8 /* segment shared with another file */
/*
+ * Structure for XFS_IOC_GETFSMAPX.
+ *
+ * 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_GETFSMAPX
+struct getfsmapx {
+ __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_flags values - set by XFS_IOC_GETFSMAPX caller. */
+/* no flags defined yet */
+#define FMV_IF_VALID 0
+
+/* 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 allocations */
+#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
@@ -523,6 +584,7 @@ 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_GETFSMAPX _IOWR('X', 59, struct getfsmapx)
/*
* ioctl commands that replace IRIX syssgi()'s
diff --git a/libxfs/xfs_refcount.c b/libxfs/xfs_refcount.c
index 855ab54..a19cb45 100644
--- a/libxfs/xfs_refcount.c
+++ b/libxfs/xfs_refcount.c
@@ -1171,8 +1171,9 @@ xfs_refcount_decrease_extent(
* extent we find. If no shared blocks are found, flen will be set to zero.
*/
int
-xfs_refcount_find_shared(
+__xfs_refcount_find_shared(
struct xfs_mount *mp,
+ struct xfs_buf *agbp,
xfs_agnumber_t agno,
xfs_agblock_t agbno,
xfs_extlen_t aglen,
@@ -1181,23 +1182,13 @@ xfs_refcount_find_shared(
bool find_maximal)
{
struct xfs_btree_cur *cur;
- struct xfs_buf *agbp;
struct xfs_refcount_irec tmp;
- int error;
int i, have;
int bt_error = XFS_BTREE_ERROR;
+ int error;
trace_xfs_refcount_find_shared(mp, agno, agbno, aglen);
- if (xfs_always_cow) {
- *fbno = agbno;
- *flen = aglen;
- return 0;
- }
-
- error = xfs_alloc_read_agf(mp, NULL, agno, 0, &agbp);
- if (error)
- goto out;
cur = xfs_refcountbt_init_cursor(mp, NULL, agbp, agno, NULL);
/* By default, skip the whole range */
@@ -1272,14 +1263,46 @@ done:
out_error:
xfs_btree_del_cursor(cur, bt_error);
- xfs_buf_relse(agbp);
-out:
if (error)
trace_xfs_refcount_find_shared_error(mp, agno, error, _RET_IP_);
return error;
}
/*
+ * Given an AG extent, find the lowest-numbered run of shared blocks within
+ * that range and return the range in fbno/flen.
+ */
+int
+xfs_refcount_find_shared(
+ struct xfs_mount *mp,
+ xfs_agnumber_t agno,
+ xfs_agblock_t agbno,
+ xfs_extlen_t aglen,
+ xfs_agblock_t *fbno,
+ xfs_extlen_t *flen,
+ bool find_maximal)
+{
+ struct xfs_buf *agbp;
+ int error;
+
+ if (xfs_always_cow) {
+ *fbno = agbno;
+ *flen = aglen;
+ return 0;
+ }
+
+ error = xfs_alloc_read_agf(mp, NULL, agno, 0, &agbp);
+ if (error)
+ return error;
+
+ error = __xfs_refcount_find_shared(mp, agbp, agno, agbno, aglen,
+ fbno, flen, find_maximal);
+
+ xfs_buf_relse(agbp);
+ return error;
+}
+
+/*
* Recovering CoW Blocks After a Crash
*
* Due to the way that the copy on write mechanism works, there's a window of
diff --git a/libxfs/xfs_refcount.h b/libxfs/xfs_refcount.h
index 6665eeb..44b0346 100644
--- a/libxfs/xfs_refcount.h
+++ b/libxfs/xfs_refcount.h
@@ -53,6 +53,10 @@ extern int xfs_refcount_finish_one(struct xfs_trans *tp,
xfs_fsblock_t startblock, xfs_extlen_t blockcount,
xfs_extlen_t *adjusted, struct xfs_btree_cur **pcur);
+extern int __xfs_refcount_find_shared(struct xfs_mount *mp,
+ struct xfs_buf *agbp, xfs_agnumber_t agno, xfs_agblock_t agbno,
+ xfs_extlen_t aglen, xfs_agblock_t *fbno, xfs_extlen_t *flen,
+ bool find_maximal);
extern int xfs_refcount_find_shared(struct xfs_mount *mp, xfs_agnumber_t agno,
xfs_agblock_t agbno, xfs_extlen_t aglen, xfs_agblock_t *fbno,
xfs_extlen_t *flen, bool find_maximal);
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