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| * | | | | | | | | | | | | | | | | | [readdir] convert hostfsAl Viro2013-06-29
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| * | | | | | | | | | | | | | | | | | [readdir] convert afsAl Viro2013-06-29
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| * | | | | | | | | | | | | | | | | | [readdir] convert ncpfsAl Viro2013-06-29
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| * | | | | | | | | | | | | | | | | | [readdir] convert hfsplusAl Viro2013-06-29
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| * | | | | | | | | | | | | | | | | | [readdir] convert hfsAl Viro2013-06-29
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| * | | | | | | | | | | | | | | | | | [readdir] convert befsAl Viro2013-06-29
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| * | | | | | | | | | | | | | | | | | [readdir] convert cifsAl Viro2013-06-29
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| * | | | | | | | | | | | | | | | | | [readdir] convert freevxfsAl Viro2013-06-29
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| * | | | | | | | | | | | | | | | | | [readdir] convert fuseAl Viro2013-06-29
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| * | | | | | | | | | | | | | | | | | [readdir] convert hpfsAl Viro2013-06-29
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| * | | | | | | | | | | | | | | | | | reiserfs: switch reiserfs_readdir_dentry to inodeAl Viro2013-06-29
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | ... and clean the callers up a bit Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| * | | | | | | | | | | | | | | | | | reiserfs: is_privroot_deh() needs only directory inode, actuallyAl Viro2013-06-29
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | ... and that - only to get the superblock. Privroot is a directory and we don't allow hardlinks to those... Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| * | | | | | | | | | | | | | | | | | [readdir] convert reiserfsAl Viro2013-06-29
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| * | | | | | | | | | | | | | | | | | [readdir] convert ntfsAl Viro2013-06-29
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| * | | | | | | | | | | | | | | | | | [readdir] convert isofsAl Viro2013-06-29
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| * | | | | | | | | | | | | | | | | | [readdir] convert jffs2Al Viro2013-06-29
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| * | | | | | | | | | | | | | | | | | [readdir] convert f2fsAl Viro2013-06-29
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| * | | | | | | | | | | | | | | | | | [readdir] convert 9pAl Viro2013-06-29
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| * | | | | | | | | | | | | | | | | | [readdir] convert affsAl Viro2013-06-29
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| * | | | | | | | | | | | | | | | | | [readdir] convert adfsAl Viro2013-06-29
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| * | | | | | | | | | | | | | | | | | [readdir] convert logfsAl Viro2013-06-29
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| * | | | | | | | | | | | | | | | | | [readdir] convert jfsAl Viro2013-06-29
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| * | | | | | | | | | | | | | | | | | [readdir] convert cephAl Viro2013-06-29
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| * | | | | | | | | | | | | | | | | | [readdir] convert nfsAl Viro2013-06-29
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| * | | | | | | | | | | | | | | | | | [readdir] convert ext4Al Viro2013-06-29
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | and trim the living hell out bogosities in inline dir case Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| * | | | | | | | | | | | | | | | | | [readdir] convert qnx6Al Viro2013-06-29
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| * | | | | | | | | | | | | | | | | | [readdir] convert qnx4Al Viro2013-06-29
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | ... and use strnlen() instead of strlen() - it's done on untrusted data, after all. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| * | | | | | | | | | | | | | | | | | [readdir] convert omfsAl Viro2013-06-29
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| * | | | | | | | | | | | | | | | | | [readdir] convert nilfs2Al Viro2013-06-29
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| * | | | | | | | | | | | | | | | | | [readdir] convert sysfsAl Viro2013-06-29
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | get rid of the kludges in sysfs_readdir() Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| * | | | | | | | | | | | | | | | | | [readdir] convert gfs2Al Viro2013-06-29
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| * | | | | | | | | | | | | | | | | | [readdir] convert exofsAl Viro2013-06-29
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| * | | | | | | | | | | | | | | | | | [readdir] convert bfsAl Viro2013-06-29
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | ... and get rid of that ridiculous mutex in bfs_readdir() Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| * | | | | | | | | | | | | | | | | | [readdir] convert procfsAl Viro2013-06-29
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| * | | | | | | | | | | | | | | | | | [readdir] convert openpromfsAl Viro2013-06-29
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | what the hell is op_mutex for, BTW? Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| * | | | | | | | | | | | | | | | | | [readdir] convert efsAl Viro2013-06-29
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | * sanity checks belong before risky operation, not after it * don't quit as soon as we'd found an entry Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| * | | | | | | | | | | | | | | | | | [readdir] convert configfsAl Viro2013-06-29
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| * | | | | | | | | | | | | | | | | | [readdir] convert romfsAl Viro2013-06-29
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| * | | | | | | | | | | | | | | | | | [readdir] convert squashfsAl Viro2013-06-29
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| * | | | | | | | | | | | | | | | | | [readdir] convert ubifsAl Viro2013-06-29
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| * | | | | | | | | | | | | | | | | | [readdir] convert udfAl Viro2013-06-29
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| * | | | | | | | | | | | | | | | | | [readdir] convert ext3Al Viro2013-06-29
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | new helper: dir_relax(inode). Call when you are in location that will _not_ be invalidated by directory modifications (block boundary, in case of ext*). Returns whether the directory has survived (dropping i_mutex allows rmdir to kill the sucker; if it returns false to us, ->iterate() is obviously done) Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| * | | | | | | | | | | | | | | | | | [readdir] switch dcache_readdir() users to ->iterate()Al Viro2013-06-29
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | new helpers - dir_emit_dot(file, ctx, dentry), dir_emit_dotdot(file, ctx), dir_emit_dots(file, ctx). Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| * | | | | | | | | | | | | | | | | | [readdir] simple local unixlike: switch to ->iterate()Al Viro2013-06-29
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | ext2, ufs, minix, sysv Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| * | | | | | | | | | | | | | | | | | [readdir] introduce ->iterate(), ctx->pos, dir_emit()Al Viro2013-06-29
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | New method - ->iterate(file, ctx). That's the replacement for ->readdir(); it takes callback from ctx->actor, uses ctx->pos instead of file->f_pos and calls dir_emit(ctx, ...) instead of filldir(data, ...). It does *not* update file->f_pos (or look at it, for that matter); iterate_dir() does the update. Note that dir_emit() takes the offset from ctx->pos (and eventually filldir_t will lose that argument). Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| * | | | | | | | | | | | | | | | | | [readdir] introduce iterate_dir() and dir_contextAl Viro2013-06-29
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | iterate_dir(): new helper, replacing vfs_readdir(). struct dir_context: contains the readdir callback (and will get more stuff in it), embedded into whatever data that callback wants to deal with; eventually, we'll be passing it to ->readdir() replacement instead of (data,filldir) pair. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| * | | | | | | | | | | | | | | | | | compat.c: LOOP_CLR_FD is taken care of in loop.c itself...Al Viro2013-06-29
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* | | | | | | | | | | | | | | | | | | sync: don't block the flusher thread waiting on IODave Chinner2013-07-02
| |_|_|_|_|_|_|_|_|_|_|_|/ / / / / / |/| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When sync does it's WB_SYNC_ALL writeback, it issues data Io and then immediately waits for IO completion. This is done in the context of the flusher thread, and hence completely ties up the flusher thread for the backing device until all the dirty inodes have been synced. On filesystems that are dirtying inodes constantly and quickly, this means the flusher thread can be tied up for minutes per sync call and hence badly affect system level write IO performance as the page cache cannot be cleaned quickly. We already have a wait loop for IO completion for sync(2), so cut this out of the flusher thread and delegate it to wait_sb_inodes(). Hence we can do rapid IO submission, and then wait for it all to complete. Effect of sync on fsmark before the patch: FSUse% Count Size Files/sec App Overhead ..... 0 640000 4096 35154.6 1026984 0 720000 4096 36740.3 1023844 0 800000 4096 36184.6 916599 0 880000 4096 1282.7 1054367 0 960000 4096 3951.3 918773 0 1040000 4096 40646.2 996448 0 1120000 4096 43610.1 895647 0 1200000 4096 40333.1 921048 And a single sync pass took: real 0m52.407s user 0m0.000s sys 0m0.090s After the patch, there is no impact on fsmark results, and each individual sync(2) operation run concurrently with the same fsmark workload takes roughly 7s: real 0m6.930s user 0m0.000s sys 0m0.039s IOWs, sync is 7-8x faster on a busy filesystem and does not have an adverse impact on ongoing async data write operations. Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Jan Kara <jack@suse.cz> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | | | | | | | | | | | | | | | | | Merge branch 'for-linus' of ↵Linus Torvalds2013-06-29
|\| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs Pull ubifs fixes from Al Viro: "A couple of ubifs readdir/lseek race fixes. Stable fodder, really nasty..." * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: UBIFS: fix a horrid bug UBIFS: prepare to fix a horrid bug
| * | | | | | | | | | | | | | | | | UBIFS: fix a horrid bugArtem Bityutskiy2013-06-29
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>