Resize of a filesystem image does not work as expected. This has been confusing and can have bad consequences as people have reported, resizing the wrong filesystem.
Signed-off-by: David Sterba <dste...@suse.cz> --- Documentation/btrfs-filesystem.asciidoc | 9 +++++++-- cmds-filesystem.c | 15 +++++++++++++++ 2 files changed, 22 insertions(+), 2 deletions(-) diff --git a/Documentation/btrfs-filesystem.asciidoc b/Documentation/btrfs-filesystem.asciidoc index cefdc8ea93dd..630483d8c114 100644 --- a/Documentation/btrfs-filesystem.asciidoc +++ b/Documentation/btrfs-filesystem.asciidoc @@ -89,8 +89,13 @@ NOTE: the maximum allowable length shall be less than 256 chars // Some wording are extracted by the resize2fs man page *resize* [<devid>:][+/-]<size>[kKmMgGtTpPeE]|[<devid>:]max <path>:: -Resize a filesystem identified by <path> for the underlying device -devid *online*. + +Resize a mounted filesystem identified by directory <path>. A particular device +can be resized by specifying a <devid>. ++ +If <path> is a file containing a btrfs image then resize does not work as +expected and does not resize the image. This would resize the underlying +filesytem instead. ++ The devid can be found with *btrfs filesystem show* and defaults to 1 if not specified. The <size> parameter specifies the new size of the filesystem. diff --git a/cmds-filesystem.c b/cmds-filesystem.c index 188dbf0c48d2..d62aef6833ce 100644 --- a/cmds-filesystem.c +++ b/cmds-filesystem.c @@ -1234,6 +1234,7 @@ static int cmd_resize(int argc, char **argv) int fd, res, len, e; char *amount, *path; DIR *dirstream = NULL; + struct stat st; if (check_argc_exact(argc, 3)) usage(cmd_resize_usage); @@ -1248,6 +1249,20 @@ static int cmd_resize(int argc, char **argv) return 1; } + res = stat(path, &st); + if (res < 0) { + fprintf(stderr, "ERROR: resize: cannot stat %s: %s\n", + path, strerror(errno)); + return 1; + } + if (!S_ISDIR(st.st_mode)) { + fprintf(stderr, + "ERROR: resize works on mounted filesystems and accepts only\n" + "directories as argument. Passing file containing a btrfs image\n" + "would resize the underlying filesytem instead of the image.\n"); + return 1; + } + fd = open_file_or_dir(path, &dirstream); if (fd < 0) { fprintf(stderr, "ERROR: can't access '%s'\n", path); -- 2.1.3 -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html