| Message ID | 20180903113115.13609-1-kilobyte@angband.pl (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [v2] btrfs-progs: defrag: open files RO on new enough kernels | expand |
On 3.09.2018 14:31, Adam Borowski wrote: > Defragging an executable conflicts both way with it being run, resulting in > ETXTBSY. This either makes defrag fail or prevents the program from being > executed. > > Kernels 4.19-rc1 and later allow defragging files you could have possibly > opened rw, even if the passed descriptor is ro. > > Signed-off-by: Adam Borowski <kilobyte@angband.pl> So this commit really seems to be the userspace counterpart of 616d374efa23 ("btrfs: allow defrag on a file opened read-only that has rw permissions") as such IMO it will be good if you reference it. > --- > v2: more eloquent description; root can't defrag RO on old kernels (unlike > dedupe) > > > cmds-filesystem.c | 10 ++++++++-- > 1 file changed, 8 insertions(+), 2 deletions(-) > > diff --git a/cmds-filesystem.c b/cmds-filesystem.c > index 06c8311b..17e992a3 100644 > --- a/cmds-filesystem.c > +++ b/cmds-filesystem.c > @@ -26,6 +26,7 @@ > #include <ftw.h> > #include <mntent.h> > #include <linux/limits.h> > +#include <linux/version.h> > #include <getopt.h> > > #include <btrfsutil.h> > @@ -39,12 +40,14 @@ > #include "list_sort.h" > #include "disk-io.h" > #include "help.h" > +#include "fsfeatures.h" > > /* > * for btrfs fi show, we maintain a hash of fsids we've already printed. > * This way we don't print dups if a given FS is mounted more than once. > */ > static struct seen_fsid *seen_fsid_hash[SEEN_FSID_HASH_SIZE] = {NULL,}; > +static mode_t defrag_ro = O_RDONLY; > > static const char * const filesystem_cmd_group_usage[] = { > "btrfs filesystem [<group>] <command> [<args>]", > @@ -877,7 +880,7 @@ static int defrag_callback(const char *fpath, const struct stat *sb, > if ((typeflag == FTW_F) && S_ISREG(sb->st_mode)) { > if (defrag_global_verbose) > printf("%s\n", fpath); > - fd = open(fpath, O_RDWR); > + fd = open(fpath, defrag_ro); > if (fd < 0) { > goto error; > } > @@ -914,6 +917,9 @@ static int cmd_filesystem_defrag(int argc, char **argv) > int compress_type = BTRFS_COMPRESS_NONE; > DIR *dirstream; > > + if (get_running_kernel_version() < KERNEL_VERSION(4,19,0)) > + defrag_ro = O_RDWR; I completely missed those lines in the previous posting, so alongside the context information of the kernel commit this makes sense. However, defrag_ro is a really bad name because there are case where, well, it's not going to be ro, is it ? How about something like "defrag_open_mode" or "defrag_open_flags" or something neutral which won't be implying the mode of operation. > + > /* > * Kernel has a different default (256K) that is supposed to be safe, > * but it does not defragment very well. The 32M will likely lead to > @@ -1014,7 +1020,7 @@ static int cmd_filesystem_defrag(int argc, char **argv) > int defrag_err = 0; > > dirstream = NULL; > - fd = open_file_or_dir(argv[i], &dirstream); > + fd = open_file_or_dir3(argv[i], &dirstream, defrag_ro); > if (fd < 0) { > error("cannot open %s: %m", argv[i]); > ret = -errno; >
diff --git a/cmds-filesystem.c b/cmds-filesystem.c index 06c8311b..17e992a3 100644 --- a/cmds-filesystem.c +++ b/cmds-filesystem.c @@ -26,6 +26,7 @@ #include <ftw.h> #include <mntent.h> #include <linux/limits.h> +#include <linux/version.h> #include <getopt.h> #include <btrfsutil.h> @@ -39,12 +40,14 @@ #include "list_sort.h" #include "disk-io.h" #include "help.h" +#include "fsfeatures.h" /* * for btrfs fi show, we maintain a hash of fsids we've already printed. * This way we don't print dups if a given FS is mounted more than once. */ static struct seen_fsid *seen_fsid_hash[SEEN_FSID_HASH_SIZE] = {NULL,}; +static mode_t defrag_ro = O_RDONLY; static const char * const filesystem_cmd_group_usage[] = { "btrfs filesystem [<group>] <command> [<args>]", @@ -877,7 +880,7 @@ static int defrag_callback(const char *fpath, const struct stat *sb, if ((typeflag == FTW_F) && S_ISREG(sb->st_mode)) { if (defrag_global_verbose) printf("%s\n", fpath); - fd = open(fpath, O_RDWR); + fd = open(fpath, defrag_ro); if (fd < 0) { goto error; } @@ -914,6 +917,9 @@ static int cmd_filesystem_defrag(int argc, char **argv) int compress_type = BTRFS_COMPRESS_NONE; DIR *dirstream; + if (get_running_kernel_version() < KERNEL_VERSION(4,19,0)) + defrag_ro = O_RDWR; + /* * Kernel has a different default (256K) that is supposed to be safe, * but it does not defragment very well. The 32M will likely lead to @@ -1014,7 +1020,7 @@ static int cmd_filesystem_defrag(int argc, char **argv) int defrag_err = 0; dirstream = NULL; - fd = open_file_or_dir(argv[i], &dirstream); + fd = open_file_or_dir3(argv[i], &dirstream, defrag_ro); if (fd < 0) { error("cannot open %s: %m", argv[i]); ret = -errno;
Defragging an executable conflicts both way with it being run, resulting in ETXTBSY. This either makes defrag fail or prevents the program from being executed. Kernels 4.19-rc1 and later allow defragging files you could have possibly opened rw, even if the passed descriptor is ro. Signed-off-by: Adam Borowski <kilobyte@angband.pl> --- v2: more eloquent description; root can't defrag RO on old kernels (unlike dedupe) cmds-filesystem.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-)