We already use them for openat() and friends, but fchdir() also wants to be able to use O_PATH file descriptors. This should make it comparable to the O_SEARCH of Solaris. In particular, O_PATH allows you to access (not-quite-open) a directory you don't have read persmission to, only execute permission. Noticed during development of multithread support for ksh93. Reported-by: ольга крыжановская <olga.kryzhanovska@gmail.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: stable@kernel.org # O_PATH introduced in 3.0+ Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> (cherry picked from commit 332a2e1244bd08b9e3ecd378028513396a004a24) Signed-off-by: Dominik Sliwa <dominik.sliwa@toradex.com> Acked-by: Marcel Ziswiler <marcel.ziswiler@toradex.com>
We already use them for openat() and friends, but fstat() also wants to be able to use O_PATH file descriptors. This should make it more directly comparable to the O_SEARCH of Solaris. Note that you could already do the same thing with "fstatat()" and an empty path, but just doing "fstat()" directly is simpler and faster, so there is no reason not to just allow it directly. See also commit 332a2e1244bd, which did the same thing for fchdir, for the same reasons. Reported-by: ольга крыжановская <olga.kryzhanovska@gmail.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: stable@kernel.org # O_PATH introduced in 3.0+ Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> (cherry picked from commit 55815f70147dcfa3ead5738fd56d3574e2e3c1c2) Signed-off-by: Dominik Sliwa <dominik.sliwa@toradex.com> Acked-by: Marcel Ziswiler <marcel.ziswiler@toradex.com>
Use the *_light() versions that properly avoid doing the file user count updates when they are unnecessary. Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> (cherry picked from commit e994defb7b6813ba6fa7a2a36e86d2455ad1dc35) Signed-off-by: Dominik Sliwa <dominik.sliwa@toradex.com> Acked-by: Marcel Ziswiler <marcel.ziswiler@toradex.com>
Conflicts: drivers/mtd/ubi/ubi.h drivers/mtd/ubi/wl.c
While in list_for_each_entry() of yaffs_flush_inodes, the fs code can delete inodes. This leads to an endless loop which causes a softlockup. Typically this happend in sync_supers when creating and deleting files while under CPU load. This fix checks whether we get twice the same inode. If this is true, we just retry again. This is an alternative fix to the proposed fix Jisheng Zhang: yaffs: fix softlockup cauesed by inode deleted when scanning s_inodes list http://www.aleph1.co.uk/lurker/message/20110831.075307.3cfeacdf.fr.html
The fsync function in the fs.h header file in our kernel version has two additional function introduced by this commit: 02c24a82187d5a628c68edfe71ae60dc135cd178 fs: push i_mutex and filemap_write_and_wait down into ->fsync() handlers Update the function prototype for YAFFS2 too to avoid missinterpreted datasync parameter and to avoid warnings.
Al Viro pointed me to the fact that '->readdir()' and '->llseek()' have no mutual exclusion, which means the 'ubifs_dir_llseek()' can be run while we are in the middle of 'ubifs_readdir()'. This means that 'file->private_data' can be freed while 'ubifs_readdir()' uses it, and this is a very bad bug: not only 'ubifs_readdir()' can return garbage, but this may corrupt memory and lead to all kinds of problems like crashes an security holes. This patch fixes the problem by using the 'file->f_version' field, which '->llseek()' always unconditionally sets to zero. We set it to 1 in 'ubifs_readdir()' and whenever we detect that it became 0, we know there was a seek and it is time to clear the state saved in 'file->private_data'. I tested this patch by writing a user-space program which runds readdir and seek in parallell. I could easily crash the kernel without these patches, but could not crash it with these patches. Cc: stable@vger.kernel.org Reported-by: Al Viro <viro@zeniv.linux.org.uk> Tested-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com> Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Al Viro pointed me to the fact that '->readdir()' and '->llseek()' have no mutual exclusion, which means the 'ubifs_dir_llseek()' can be run while we are in the middle of 'ubifs_readdir()'. First of all, this means that 'file->private_data' can be freed while 'ubifs_readdir()' uses it. But this particular patch does not fix the problem. This patch is only a preparation, and the fix will follow next. In this patch we make 'ubifs_readdir()' stop using 'file->f_pos' directly, because 'file->f_pos' can be changed by '->llseek()' at any point. This may lead 'ubifs_readdir()' to returning inconsistent data: directory entry names may correspond to incorrect file positions. So here we introduce a local variable 'pos', read 'file->f_pose' once at very the beginning, and then stick to 'pos'. The result of this is that when 'ubifs_dir_llseek()' changes 'file->f_pos' while we are in the middle of 'ubifs_readdir()', the latter "wins". Cc: stable@vger.kernel.org Reported-by: Al Viro <viro@zeniv.linux.org.uk> Tested-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com> Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
When mounting an UBIFS R/W volume, we have the message: UBIFS: mounted UBI device 0, volume 1, name "rootfs"(null) With this patch, we'll have: UBIFS: mounted UBI device 0, volume 1, name "rootfs" Which is, I think, what was intended. Signed-off-by: Richard Genoud <richard.genoud@gmail.com> Cc: stable@vger.kernel.org [v3.7+] Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
The UBIFS space fixup is a useful feature which allows to fixup the "broken" flash space at the time of the first mount. The "broken" space is usually the result of using a "dumb" industrial flasher which is not able to skip empty NAND pages and just writes all 0xFFs to the empty space, which has grave side-effects for UBIFS when UBIFS trise to write useful data to those empty pages. The fix-up feature works roughly like this: 1. mkfs.ubifs sets the fixup flag in UBIFS superblock when creating the image (see -F option) 2. when the file-system is mounted for the first time, UBIFS notices the fixup flag and re-writes the entire media atomically, which may take really a lot of time. 3. UBIFS clears the fixup flag in the superblock. This works fine when the file system is mounted R/W for the very first time. But it did not really work in the case when we first mount the file-system R/O, and then re-mount R/W. The reason was that we started the fixup procedure too late, which we cannot really do because we have to fixup the space before it starts being used. Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com> Reported-by: Mark Jackson <mpfj-list@mimc.co.uk> Cc: stable@vger.kernel.org # 3.0+