filefrag: Lustre changes to filefrag FIEMAP handling

Add support for multiple-device filesystems by defining a new
fe_device field in the fiemap_extent structure.  This allows
printing the filesystem-relative or linux block device number
associated with each extent of a file.  If a single filesystem
extent is mirrored to multiple block devices, the fe_device
field can be used to disambiguate the multiple copies.

If the "-l" (device-logical) option is given to filefrag, then
all extents for a particular device of a file are returned
before returning extents for the next device.  This makes it
easier to see if extent allocation within a single device is
contiguous, instead of returning all of the blocks of a file
interleaved in file-logical-offset order.

Lustre uses the high 16bits of fiemap_extent:fe_device to record
the absolute stripe number being processed, so that next fiemap
call continues from that stripe, which allows files that have
multiple objects on the same device to work properly (FLR, PFL).
Older filefrag will print the stripe number with the OST index.

Change-Id: Ifb40cc159ddc61d2296c494f0e899ac11bf88b60
Signed-off-by: Andreas Dilger <adilger@whamcloud.com>

diff --git a/lib/ext2fs/fiemap.h b/lib/ext2fs/fiemap.h
index 33ab8fb..a157c41 100644 (file)
--- a/lib/ext2fs/fiemap.h
+++ b/lib/ext2fs/fiemap.h
@@ -19,7 +19,9 @@ struct fiemap_extent {
        __u64 fe_length;   /* length in bytes for this extent */
        __u64 fe_reserved64[2];
        __u32 fe_flags;    /* FIEMAP_EXTENT_* flags for this extent */
-       __u32 fe_reserved[3];
+       __u32 fe_device;   /* device number (fs-specific if FIEMAP_EXTENT_NET)
+                           * low 16bits are used */
+       __u32 fe_reserved[2];
 };
 
 struct fiemap {
@@ -62,6 +64,7 @@ struct fiemap {
 #define FIEMAP_FLAG_SYNC       0x00000001 /* sync file data before map */
 #define FIEMAP_FLAG_XATTR      0x00000002 /* map extended attribute tree */
 #define FIEMAP_FLAG_CACHE      0x00000004 /* request caching of the extents */
+#define FIEMAP_FLAG_DEVICE_ORDER 0x40000000 /* return device ordered mapping */
 
 #define FIEMAP_FLAGS_COMPAT    (FIEMAP_FLAG_SYNC | FIEMAP_FLAG_XATTR)
 
@@ -89,5 +92,7 @@ struct fiemap {
 
 #define EXT4_FIEMAP_EXTENT_HOLE                0x08000000 /* Entry in extent status
                                                      cache for a hole*/
+/* Network filesystem flags - use a high bit, don't conflict with upstream */
+#define FIEMAP_EXTENT_NET              0x80000000 /* Data stored remotely. */
 
 #endif /* _LINUX_FIEMAP_H */

diff --git a/misc/filefrag.8.in b/misc/filefrag.8.in
index 6d56c13..7b7e424 100644 (file)
--- a/misc/filefrag.8.in
+++ b/misc/filefrag.8.in
@@ -8,7 +8,7 @@ filefrag \- report on file fragmentation
 .BI \-b blocksize
 ]
 [
-.B \-BeEkPsvVxX
+.B \-BeEklPsvVxX
 ]
 [
 .I files...
@@ -57,6 +57,9 @@ Use 1024\-byte blocksize for output (identical to '\-b1024').
 Pre-load the ext4 extent status cache for the file.  This is not
 supported on all kernels, and is only supported on ext4 file systems.
 .TP
+.B \-l
+Extents are displayed in device-logical offset order.
+.TP
 .B \-s
 Sync the file before requesting the mapping.
 .TP
@@ -72,6 +75,10 @@ Display mapping of extended attributes.
 .TP
 .B \-X
 Display extent block numbers in hexadecimal format.
+.TP
+.B \-V
+Print version number of program and library.  If given twice, also
+print the FIEMAP flags that are understood by the current version.
 .SH AUTHOR
 .B filefrag
 was written by Theodore Ts'o <tytso@mit.edu>.

diff --git a/misc/filefrag.c b/misc/filefrag.c
index eaaa90a..9dab747 100644 (file)
--- a/misc/filefrag.c
+++ b/misc/filefrag.c
@@ -61,12 +61,14 @@ int xattr_map = 0;  /* get xattr mapping */
 int force_bmap;                /* force use of FIBMAP instead of FIEMAP */
 int force_extent;      /* print output in extent format always */
 int use_extent_cache;  /* Use extent cache */
+int device_offset;     /* extents report device-relative offsets */
 int logical_width = 8;
 int physical_width = 10;
 const char *ext_fmt = "%4d: %*llu..%*llu: %*llu..%*llu: %6llu: %s\n";
 const char *hex_fmt = "%4d: %*llx..%*llx: %*llx..%*llx: %6llx: %s\n";
 
-#define FILEFRAG_FIEMAP_FLAGS_COMPAT (FIEMAP_FLAG_SYNC | FIEMAP_FLAG_XATTR)
+#define FILEFRAG_FIEMAP_FLAGS_COMPAT (FIEMAP_FLAG_SYNC | FIEMAP_FLAG_XATTR |\
+                                     FIEMAP_FLAG_DEVICE_ORDER)
 
 #define FIBMAP         _IO(0x00, 1)    /* bmap access */
 #define FIGETBSZ       _IO(0x00, 2)    /* get the block size used for bmap */
@@ -125,10 +127,10 @@ static void print_extent_header(void)
 {
        printf(" ext: %*s %*s length: %*s flags:\n",
               logical_width * 2 + 3,
-              "logical_offset:",
+              device_offset ? "device_logical:" : "logical_offset:",
               physical_width * 2 + 3, "physical_offset:",
-              physical_width + 1,
-              "expected:");
+              device_offset ? 5 : physical_width + 1,
+              device_offset ? " dev:" : "expected:");
 }
 
 static void print_flag(__u32 *flags, __u32 mask, char *buf, const char *name)
@@ -163,6 +165,8 @@ static void print_flags(__u32 fe_flags, char *flags, int len, int print_unknown)
        print_flag(&fe_flags, FIEMAP_EXTENT_SHARED, flags, "shared,");
        print_flag(&fe_flags, EXT4_FIEMAP_EXTENT_HOLE, flags, "hole,");
 
+       print_flag(&fe_flags, FIEMAP_EXTENT_NET, flags, "net,");
+
        if (!print_unknown)
                goto out;
 
@@ -200,13 +204,13 @@ static void print_extent_info(struct fiemap_extent *fm_extent, int cur_ex,
                physical_blk = fm_extent->fe_physical >> blk_shift;
        }
 
-       if (expected &&
+       if (device_offset)
+               sprintf(flags, "%04x: ", fm_extent->fe_device & 0xffff);
+       else if (expected &&
            !(fm_extent->fe_flags & FIEMAP_EXTENT_UNKNOWN) &&
            !(fm_extent->fe_flags & EXT4_FIEMAP_EXTENT_HOLE))
                sprintf(flags, ext_fmt == hex_fmt ? "%*llx: " : "%*llu: ",
                        physical_width, expected >> blk_shift);
-       else
-               sprintf(flags, "%.*s  ", physical_width, "                   ");
 
        print_flags(fm_extent->fe_flags, flags, sizeof(flags), 1);
 
@@ -244,6 +248,7 @@ static int filefrag_fiemap(int fd, int blk_shift, int *num_extents,
        unsigned long cmd = FS_IOC_FIEMAP;
        int fiemap_header_printed = 0;
        int tot_extents = 0, n = 0;
+       int previous_device = -1;
        int last = 0;
        int rc;
 
@@ -262,6 +267,12 @@ static int filefrag_fiemap(int fd, int blk_shift, int *num_extents,
        if (use_extent_cache)
                cmd = EXT4_IOC_GET_ES_CACHE;
 
+       if (device_offset) {
+               flags |= FIEMAP_FLAG_DEVICE_ORDER;
+               memset(fm_ext, 0, sizeof(struct fiemap_extent));
+       }
+
+retry_wo_device_order:
        do {
                fiemap->fm_length = ~0ULL;
                fiemap->fm_flags = flags;
@@ -276,6 +287,10 @@ static int filefrag_fiemap(int fd, int blk_shift, int *num_extents,
                                                "flags %x\n",
                                       fiemap->fm_flags);
                                fiemap_incompat_printed = 1;
+                       } else if (rc == EBADR && (fiemap->fm_flags &
+                                                  FIEMAP_FLAG_DEVICE_ORDER)) {
+                               flags &= ~FIEMAP_FLAG_DEVICE_ORDER;
+                               goto retry_wo_device_order;
                        }
                        return rc;
                }
@@ -294,9 +309,10 @@ static int filefrag_fiemap(int fd, int blk_shift, int *num_extents,
                                         fm_last.fe_length;
                        expected = fm_last.fe_physical +
                                   fm_ext[i].fe_logical - fm_last.fe_logical;
-                       if (fm_ext[i].fe_logical != 0 &&
-                           fm_ext[i].fe_physical != expected &&
-                           fm_ext[i].fe_physical != expected_dense) {
+                       if ((fm_ext[i].fe_logical != 0 &&
+                            fm_ext[i].fe_physical != expected &&
+                            fm_ext[i].fe_physical != expected_dense) ||
+                           ((fm_ext[i].fe_device & 0xffff) != previous_device)) {
                                tot_extents++;
                        } else {
                                expected = 0;
@@ -310,10 +326,23 @@ static int filefrag_fiemap(int fd, int blk_shift, int *num_extents,
                                last = 1;
                        fm_last = fm_ext[i];
                        n++;
+                       previous_device = fm_ext[i].fe_device & 0xffff;
                }
 
-               fiemap->fm_start = (fm_ext[i - 1].fe_logical +
-                                   fm_ext[i - 1].fe_length);
+               /* For DEVICE_ORDER mappings, if EXTENT_LAST not yet found then
+                * fm_start needs to be the same as it was for earlier ioctl.
+                * The first extent is used to pass the end offset and device
+                * of the last FIEMAP call.  Otherwise, we ask for extents
+                * starting from where the last mapping ended. */
+               if (flags & FIEMAP_FLAG_DEVICE_ORDER) {
+                       fm_ext[0].fe_logical =  fm_ext[i - 1].fe_logical +
+                                               fm_ext[i - 1].fe_length;
+                       fm_ext[0].fe_device =   fm_ext[i - 1].fe_device;
+                       fiemap->fm_start =      0;
+               } else {
+                       fiemap->fm_start =      fm_ext[i - 1].fe_logical +
+                                               fm_ext[i - 1].fe_length;
+               }
        } while (last == 0);
 
        *num_extents = tot_extents;
@@ -337,6 +366,7 @@ static int filefrag_fibmap(int fd, int blk_shift, int *num_extents,
        memset(&fm_ext, 0, sizeof(fm_ext));
        memset(&fm_last, 0, sizeof(fm_last));
        if (force_extent) {
+               fm_ext.fe_device = st->st_dev;
                fm_ext.fe_flags = FIEMAP_EXTENT_MERGED;
        }
 
@@ -471,6 +501,13 @@ static int frag_report(const char *filename)
                        is_ext2 = 1;
        }
 
+       /* Check if filesystem is Lustre.  Always print in extent format
+        * with 1kB blocks, using the device-relative logical offsets. */
+       if (fsinfo.f_type == LUSTRE_SUPER_MAGIC) {
+               device_offset = 1;
+               blocksize = blocksize ?: 1024;
+       }
+
        if (is_ext2) {
                long cylgroups = div_ceil(fsinfo.f_blocks, blksize * 8);
 
@@ -580,10 +617,11 @@ int main(int argc, char**argv)
        int rc = 0, c;
        int version = 0;
 
-       while ((c = getopt(argc, argv, "Bb::eEkPsvVxX")) != EOF) {
+       while ((c = getopt(argc, argv, "Bb::eEkPlsvxXV")) != EOF) {
                switch (c) {
                case 'B':
                        force_bmap++;
+                       force_extent = 0;
                        break;
                case 'b':
                        if (optarg) {
@@ -648,6 +686,9 @@ int main(int argc, char**argv)
                case 'P':
                        precache_file++;
                        break;
+               case 'l':
+                       device_offset++;
+                       break;
                case 's':
                        sync_file++;
                        break;