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| author | Karel Zak | 2016-08-17 12:28:33 +0200 |
|---|---|---|
| committer | Karel Zak | 2016-08-17 12:28:33 +0200 |
| commit | 9a94b634a343e83bfa2a9d311074e3e520abdddd (patch) | |
| tree | b1118ead3294be824b9fdbbf01449bb822aad4cf /lib/loopdev.c | |
| parent | tests: keep 'hppa' in fdisk/bsd test too (diff) | |
| download | kernel-qcow2-util-linux-9a94b634a343e83bfa2a9d311074e3e520abdddd.tar.gz kernel-qcow2-util-linux-9a94b634a343e83bfa2a9d311074e3e520abdddd.tar.xz kernel-qcow2-util-linux-9a94b634a343e83bfa2a9d311074e3e520abdddd.zip | |
losetup: add --nooverlap options
This patch introduces overlap detections and loop devices
re-use for losetup(8). We already support this feature for mount(8)
where it's enabled by default (because we mount filesystems and it's
always mistake to share the same filesystem between more loop
devices).
Stanislav has suggested to enable this feature also for losetup by
default. I'm not sure about it, IMHO it's better to keep losetup(8)
simple and stupid by default, and inform users about possible problems
and solutions in the man page.
The feature forces losetup to scan all loop devices always when new
one is requested. This maybe disadvantage (especially when we use
control-loop to avoid /sys or /dev scans) on system with huge number
of loop devices.
Co-Author: Stanislav Brabec <sbrabec@suse.cz>
Signed-off-by: Karel Zak <kzak@redhat.com>
Diffstat (limited to 'lib/loopdev.c')
| -rw-r--r-- | lib/loopdev.c | 14 |
1 files changed, 9 insertions, 5 deletions
diff --git a/lib/loopdev.c b/lib/loopdev.c index 21c8f4366..8bbde0425 100644 --- a/lib/loopdev.c +++ b/lib/loopdev.c @@ -353,10 +353,8 @@ int loopcxt_deinit_iterator(struct loopdev_cxt *lc) fclose(iter->proc); if (iter->sysblock) closedir(iter->sysblock); - iter->minors = NULL; - iter->proc = NULL; - iter->sysblock = NULL; - iter->done = 1; + + memset(iter, 0, sizeof(*iter)); return 0; } @@ -1426,8 +1424,11 @@ int loopcxt_find_unused(struct loopdev_cxt *lc) DBG(CXT, ul_debugobj(lc, "find_unused requested")); if (lc->flags & LOOPDEV_FL_CONTROL) { - int ctl = open(_PATH_DEV_LOOPCTL, O_RDWR|O_CLOEXEC); + int ctl; + + DBG(CXT, ul_debugobj(lc, "using loop-control")); + ctl = open(_PATH_DEV_LOOPCTL, O_RDWR|O_CLOEXEC); if (ctl >= 0) rc = ioctl(ctl, LOOP_CTL_GET_FREE); if (rc >= 0) { @@ -1443,6 +1444,7 @@ int loopcxt_find_unused(struct loopdev_cxt *lc) } if (rc < 0) { + DBG(CXT, ul_debugobj(lc, "using loop scan")); rc = loopcxt_init_iterator(lc, LOOPITER_FL_FREE); if (rc) return rc; @@ -1577,6 +1579,7 @@ int loopcxt_find_overlap(struct loopdev_cxt *lc, const char *filename, if (!filename) return -EINVAL; + DBG(CXT, ul_debugobj(lc, "find_overlap requested")); hasst = !stat(filename, &st); rc = loopcxt_init_iterator(lc, LOOPITER_FL_USED); @@ -1633,6 +1636,7 @@ int loopcxt_find_overlap(struct loopdev_cxt *lc, const char *filename, rc = 0; /* not found */ found: loopcxt_deinit_iterator(lc); + DBG(CXT, ul_debugobj(lc, "find_overlap done [rc=%d]", rc)); return rc; } |