hi,
there is code in setfl() which attempts to preserve the O_APPEND flag on
IS_APPEND files... however IS_APPEND files could also be opened O_RDONLY
and in that case setfl() should not require O_APPEND...
coreutils 5.93 tail -f attempts to set O_NONBLOCK even on regular files...
unfortunately if you try this on an append-only log file the result is
this:
fcntl64(3, F_GETFL) = 0x8000 (flags O_RDONLY|O_LARGEFILE)
fcntl64(3, F_SETFL, O_RDONLY|O_NONBLOCK|O_LARGEFILE) = -1 EPERM (Operation not permitted)
i offer up the patch below as one way of fixing the problem... i've tested
it fixes the problem with tail -f but haven't really tested beyond that.
(i also reported the coreutils bug upstream... it shouldn't fail imho...
<https://savannah.gnu.org/bugs/index.php?func=detailitem&item_id=15473>)
-dean
Signed-off-by: dean gaudet <[email protected]>
--- linux-2.6.14.4.orig/fs/fcntl.c 2005-10-27 17:02:08.000000000 -0700
+++ linux-2.6.14.4/fs/fcntl.c 2006-01-18 10:33:38.000000000 -0800
@@ -207,8 +207,10 @@
struct inode * inode = filp->f_dentry->d_inode;
int error = 0;
- /* O_APPEND cannot be cleared if the file is marked as append-only */
- if (!(arg & O_APPEND) && IS_APPEND(inode))
+ /* O_APPEND cannot be cleared if the file is marked as append-only
+ * and the file is open for write.
+ */
+ if (((arg ^ filp->f_flags) & O_APPEND) && IS_APPEND(inode))
return -EPERM;
/* O_NOATIME can only be set by the owner or superuser */