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author | Stanislav Brabec | 2016-07-14 15:29:21 +0200 |
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committer | Karel Zak | 2016-08-03 11:53:28 +0200 |
commit | 211e1d4609d36081fc57dd31cad6806f51b06016 (patch) | |
tree | 5572e3aa78ba4f0fff429bd3cd6c947ebd1ec3fc /lib/loopdev.c | |
parent | Add sizelimit to internal API (diff) | |
download | kernel-qcow2-util-linux-211e1d4609d36081fc57dd31cad6806f51b06016.tar.gz kernel-qcow2-util-linux-211e1d4609d36081fc57dd31cad6806f51b06016.tar.xz kernel-qcow2-util-linux-211e1d4609d36081fc57dd31cad6806f51b06016.zip |
Implement loopcxt_check_conflict()
Add a function that searches for a possible conflicting (i. e. overlaying loop
device).
Signed-off-by: Stanislav Brabec <sbrabec@suse.cz>
Diffstat (limited to 'lib/loopdev.c')
-rw-r--r-- | lib/loopdev.c | 55 |
1 files changed, 55 insertions, 0 deletions
diff --git a/lib/loopdev.c b/lib/loopdev.c index 2db80fc05..460600363 100644 --- a/lib/loopdev.c +++ b/lib/loopdev.c @@ -1566,6 +1566,61 @@ int loopcxt_find_by_backing_file(struct loopdev_cxt *lc, const char *filename, } /* + * Returns: 0 = conflict, < 0 error, 1 no conflicting device + */ +int loopcxt_check_conflict(struct loopdev_cxt *lc, const char *filename, + uint64_t offset, uint64_t sizelimit) +{ + int rc, hasst; + struct stat st; + + if (!filename) + return -EINVAL; + + hasst = !stat(filename, &st); + + rc = loopcxt_init_iterator(lc, LOOPITER_FL_USED); + if (rc) + return rc; + + while ((rc = loopcxt_next(lc)) == 0) { + uint64_t lc_sizelimit, lc_offset; + + rc = loopcxt_is_used(lc, hasst ? &st : NULL, + filename, offset, sizelimit, 0); + if (!rc) + continue; + if (rc != 1) + break; + DBG(CXT, ul_debugobj(lc, "found %s backed by %s", + loopcxt_get_device(lc), filename)); + rc = loopcxt_get_offset(lc, &lc_offset); + if (rc) { + DBG(CXT, ul_debugobj(lc, "failed to get offset for device %s", + loopcxt_get_device(lc))); + break; + } + rc = loopcxt_get_sizelimit(lc, &lc_sizelimit); + if (rc) { + DBG(CXT, ul_debugobj(lc, "failed to get sizelimit for device %s", + loopcxt_get_device(lc))); + break; + } + + if (lc_sizelimit != 0 && offset >= lc_offset + lc_sizelimit) + continue; + if (sizelimit != 0 && offset + sizelimit <= lc_offset) + continue; + DBG(CXT, ul_debugobj(lc, "overlapping loop device %s", + loopcxt_get_device(lc))); + rc = 0; + break; + } + loopcxt_deinit_iterator(lc); + return rc; +} + +/* * Returns allocated string with device name */ char *loopdev_find_by_backing_file(const char *filename, uint64_t offset, uint64_t sizelimit, int flags) |