Commit b41572e929221b0d87f529106cdf12185ee84bca
Committed by
Linus Torvalds
1 parent
ce8d2cdf3d
Exists in
master
and in
4 other branches
r/o bind mounts: rearrange may_open() to be r/o friendly
may_open() calls vfs_permission() before it does checks for IS_RDONLY(inode). It checks _again_ inside of vfs_permission(). The check inside of vfs_permission() is going away eventually. With the mnt_want/drop_write() functions, all of the r/o checks (except for this one) are consistently done before calling permission(). Because of this, I'd like to use permission() to hold a debugging check to make sure that the mnt_want/drop_write() calls are actually being made. So, to do this: 1. remove the IS_RDONLY() check from permission() 2. enforce that you must mnt_want_write() before even calling permission() 3. actually add the debugging check to permission() We need to rearrange may_open() to do r/o checks before calling permission(). Here's the patch. Signed-off-by: Dave Hansen <haveblue@us.ibm.com> Cc: Christoph Hellwig <hch@lst.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Showing 1 changed file with 4 additions and 4 deletions Side-by-side Diff
fs/namei.c
... | ... | @@ -1604,10 +1604,6 @@ |
1604 | 1604 | if (S_ISDIR(inode->i_mode) && (flag & FMODE_WRITE)) |
1605 | 1605 | return -EISDIR; |
1606 | 1606 | |
1607 | - error = vfs_permission(nd, acc_mode); | |
1608 | - if (error) | |
1609 | - return error; | |
1610 | - | |
1611 | 1607 | /* |
1612 | 1608 | * FIFO's, sockets and device files are special: they don't |
1613 | 1609 | * actually live on the filesystem itself, and as such you |
... | ... | @@ -1622,6 +1618,10 @@ |
1622 | 1618 | flag &= ~O_TRUNC; |
1623 | 1619 | } else if (IS_RDONLY(inode) && (flag & FMODE_WRITE)) |
1624 | 1620 | return -EROFS; |
1621 | + | |
1622 | + error = vfs_permission(nd, acc_mode); | |
1623 | + if (error) | |
1624 | + return error; | |
1625 | 1625 | /* |
1626 | 1626 | * An append-only file must be opened in append mode for writing. |
1627 | 1627 | */ |