From mboxrd@z Thu Jan 1 00:00:00 1970 From: Yang Xu Date: Tue, 30 Jul 2019 18:42:10 +0800 Subject: [LTP] [PATCH v6 1/3] lib: alter find_free_loopdev() In-Reply-To: <20190729130107.GA27006@rei.lan> References: <5D30200B.4050306@cn.fujitsu.com> <1564030915-3211-1-git-send-email-xuyang2018.jy@cn.fujitsu.com> <20190729130107.GA27006@rei.lan> Message-ID: <5D401F02.5080209@cn.fujitsu.com> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: ltp@lists.linux.it > Hi! >> +int tst_find_free_loopdev(const char *path, size_t path_len); >> /* >> * Reads test block device stat file and returns the bytes written since the >> * last call of this function. >> diff --git a/lib/tst_device.c b/lib/tst_device.c >> index 65fcc1337..f2516fb08 100644 >> --- a/lib/tst_device.c >> +++ b/lib/tst_device.c >> @@ -53,22 +53,22 @@ static const char *dev_variants[] = { >> "/dev/block/loop%i" >> }; >> >> -static int set_dev_path(int dev) >> +static int set_dev_path(int dev, char *path, size_t path_len) >> { >> unsigned int i; >> struct stat st; >> >> for (i = 0; i< ARRAY_SIZE(dev_variants); i++) { >> - snprintf(dev_path, sizeof(dev_path), dev_variants[i], dev); >> + snprintf(path, path_len, dev_variants[i], dev); >> >> - if (stat(dev_path,&st) == 0&& S_ISBLK(st.st_mode)) >> + if (stat(path,&st) == 0&& S_ISBLK(st.st_mode)) >> return 1; >> } >> >> return 0; >> } >> >> -static int find_free_loopdev(void) >> +int tst_find_free_loopdev(char *path, size_t path_len) >> { >> int ctl_fd, dev_fd, rc, i; >> struct loop_info loopinfo; >> @@ -80,12 +80,14 @@ static int find_free_loopdev(void) >> rc = ioctl(ctl_fd, LOOP_CTL_GET_FREE); >> close(ctl_fd); >> if (rc>= 0) { >> - set_dev_path(rc); >> - tst_resm(TINFO, "Found free device '%s'", dev_path); >> - return 0; >> + if (path) >> + set_dev_path(rc, path, path_len); >> + tst_resm(TINFO, "Found free device %d '%s'", >> + rc, path ?: ""); >> + return rc; >> } >> tst_resm(TINFO, "Couldn't find free loop device"); >> - return 1; >> + return -1; >> } >> >> switch (errno) { >> @@ -104,24 +106,24 @@ static int find_free_loopdev(void) >> * Older way is to iterate over /dev/loop%i and /dev/loop/%i and try >> * LOOP_GET_STATUS ioctl() which fails for free loop devices. >> */ >> - for (i = 0; i< 256; i++) { >> + for (i = 0; path&& i< 256; i++) { > There is still a small problem here in the fallback code for older > kernels. The way we detect a free device there is by opening the device > and doing the LOOP_GET_STATUS ioctl(). So by disabling this loop if path > is not set we broke the detection on older kernels when NULL is passed > to the function. > > We should work with a local temporary path in this loop and copy it over > to the path if we are succesfull and if path is not NULL. > Hi Cyril Thanks for pointing out it. I will fix it on next version. as below: int tst_find_free_loopdev(char *path, size_t path_len) { int ctl_fd, dev_fd, rc, i; struct loop_info loopinfo; + char buf[1024]; /* since Linux 3.1 */ ctl_fd = open(LOOP_CONTROL_FILE, O_RDWR); @@ -80,12 +81,14 @@ static int find_free_loopdev(void) rc = ioctl(ctl_fd, LOOP_CTL_GET_FREE); close(ctl_fd); if (rc>= 0) { - set_dev_path(rc); - tst_resm(TINFO, "Found free device '%s'", dev_path); - return 0; + if (path) + set_dev_path(rc, path, path_len); + tst_resm(TINFO, "Found free device %d '%s'", + rc, path ?: ""); + return rc; } tst_resm(TINFO, "Couldn't find free loop device"); - return 1; + return -1; } static int find_free_loopdev(void) */ for (i = 0; i< 256; i++) { - if (!set_dev_path(i)) + if (!set_dev_path(i, buf, sizeof(buf))) continue; - dev_fd = open(dev_path, O_RDONLY); + dev_fd = open(buf, O_RDONLY); if (dev_fd< 0) continue; if (ioctl(dev_fd, LOOP_GET_STATUS,&loopinfo) == 0) { - tst_resm(TINFO, "Device '%s' in use", dev_path); + tst_resm(TINFO, "Device '%s' in use", buf); } else { if (errno != ENXIO) continue; - tst_resm(TINFO, "Found free device '%s'", dev_path); + tst_resm(TINFO, "Found free device '%s'", buf); close(dev_fd); - return 0; + if (path != NULL) + strcpy(path, buf); + return i; } Thanks Yang Xu >> - if (!set_dev_path(i)) >> + if (!set_dev_path(i, path, path_len)) >> continue; >> >> - dev_fd = open(dev_path, O_RDONLY); >> + dev_fd = open(path, O_RDONLY); >> >> if (dev_fd< 0) >> continue; >> >> if (ioctl(dev_fd, LOOP_GET_STATUS,&loopinfo) == 0) { >> - tst_resm(TINFO, "Device '%s' in use", dev_path); >> + tst_resm(TINFO, "Device '%s' in use", path); >> } else { >> if (errno != ENXIO) >> continue; >> - tst_resm(TINFO, "Found free device '%s'", dev_path); >> + tst_resm(TINFO, "Found free device '%s'", path); >> close(dev_fd); >> - return 0; >> + return i; >> } >> >> close(dev_fd); >> @@ -129,7 +131,7 @@ static int find_free_loopdev(void) >> >> tst_resm(TINFO, "No free devices found"); >> >> - return 1; >> + return -1; >> }