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author | Christoph Hellwig <hch@infradead.org> | 2007-12-07 14:07:53 +1100 |
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committer | Lachlan McIlroy <lachlan@redback.melbourne.sgi.com> | 2007-12-10 13:47:15 +1100 |
commit | e89bc612d61edbcefaeb6f2244f86c0f3ec89d23 (patch) | |
tree | 077e87a470b1ae2b8660fcc02f77f7b303e4c0f7 /fs/xfs | |
parent | a7430847fcb19297d6db833f35b9c9645c4a6395 (diff) | |
download | talos-obmc-linux-e89bc612d61edbcefaeb6f2244f86c0f3ec89d23.tar.gz talos-obmc-linux-e89bc612d61edbcefaeb6f2244f86c0f3ec89d23.zip |
[XFS] revert to double-buffering readdir
The current readdir implementation deadlocks on a btree buffers locks
because nfsd calls back into ->lookup from the filldir callback. The only
short-term fix for this is to revert to the old inefficient
double-buffering scheme.
SGI-PV: 973377
SGI-Modid: xfs-linux-melb:xfs-kern:30201a
Signed-off-by: Christoph Hellwig <hch@infradead.org>
Signed-off-by: David Chinner <dgc@sgi.com>
Signed-off-by: Lachlan McIlroy <lachlan@sgi.com>
Diffstat (limited to 'fs/xfs')
-rw-r--r-- | fs/xfs/linux-2.6/xfs_file.c | 124 |
1 files changed, 124 insertions, 0 deletions
diff --git a/fs/xfs/linux-2.6/xfs_file.c b/fs/xfs/linux-2.6/xfs_file.c index fb8dd34041eb..54c564693d93 100644 --- a/fs/xfs/linux-2.6/xfs_file.c +++ b/fs/xfs/linux-2.6/xfs_file.c @@ -218,6 +218,15 @@ xfs_vm_fault( } #endif /* CONFIG_XFS_DMAPI */ +/* + * Unfortunately we can't just use the clean and simple readdir implementation + * below, because nfs might call back into ->lookup from the filldir callback + * and that will deadlock the low-level btree code. + * + * Hopefully we'll find a better workaround that allows to use the optimal + * version at least for local readdirs for 2.6.25. + */ +#if 0 STATIC int xfs_file_readdir( struct file *filp, @@ -249,6 +258,121 @@ xfs_file_readdir( return -error; return 0; } +#else + +struct hack_dirent { + int namlen; + loff_t offset; + u64 ino; + unsigned int d_type; + char name[]; +}; + +struct hack_callback { + char *dirent; + size_t len; + size_t used; +}; + +STATIC int +xfs_hack_filldir( + void *__buf, + const char *name, + int namlen, + loff_t offset, + u64 ino, + unsigned int d_type) +{ + struct hack_callback *buf = __buf; + struct hack_dirent *de = (struct hack_dirent *)(buf->dirent + buf->used); + + if (buf->used + sizeof(struct hack_dirent) + namlen > buf->len) + return -EINVAL; + + de->namlen = namlen; + de->offset = offset; + de->ino = ino; + de->d_type = d_type; + memcpy(de->name, name, namlen); + buf->used += sizeof(struct hack_dirent) + namlen; + return 0; +} + +STATIC int +xfs_file_readdir( + struct file *filp, + void *dirent, + filldir_t filldir) +{ + struct inode *inode = filp->f_path.dentry->d_inode; + xfs_inode_t *ip = XFS_I(inode); + struct hack_callback buf; + struct hack_dirent *de; + int error; + loff_t size; + int eof = 0; + xfs_off_t start_offset, curr_offset, offset; + + /* + * Try fairly hard to get memory + */ + buf.len = PAGE_CACHE_SIZE; + do { + buf.dirent = kmalloc(buf.len, GFP_KERNEL); + if (buf.dirent) + break; + buf.len >>= 1; + } while (buf.len >= 1024); + + if (!buf.dirent) + return -ENOMEM; + + curr_offset = filp->f_pos; + if (curr_offset == 0x7fffffff) + offset = 0xffffffff; + else + offset = filp->f_pos; + + while (!eof) { + int reclen; + start_offset = offset; + + buf.used = 0; + error = -xfs_readdir(ip, &buf, buf.len, &offset, + xfs_hack_filldir); + if (error || offset == start_offset) { + size = 0; + break; + } + + size = buf.used; + de = (struct hack_dirent *)buf.dirent; + while (size > 0) { + if (filldir(dirent, de->name, de->namlen, + curr_offset & 0x7fffffff, + de->ino, de->d_type)) { + goto done; + } + + reclen = sizeof(struct hack_dirent) + de->namlen; + size -= reclen; + curr_offset = de->offset /* & 0x7fffffff */; + de = (struct hack_dirent *)((char *)de + reclen); + } + } + + done: + if (!error) { + if (size == 0) + filp->f_pos = offset & 0x7fffffff; + else if (de) + filp->f_pos = curr_offset; + } + + kfree(buf.dirent); + return error; +} +#endif STATIC int xfs_file_mmap( |