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author | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 22:20:36 (GMT) |
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committer | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 22:20:36 (GMT) |
commit | 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch) | |
tree | 0bba044c4ce775e45a88a51686b5d9f90697ea9d /fs/afs/dir.c | |
download | linux-fsl-qoriq-1da177e4c3f41524e886b7f1b8a0c1fc7321cac2.tar.xz |
Linux-2.6.12-rc2
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.
Let it rip!
Diffstat (limited to 'fs/afs/dir.c')
-rw-r--r-- | fs/afs/dir.c | 666 |
1 files changed, 666 insertions, 0 deletions
diff --git a/fs/afs/dir.c b/fs/afs/dir.c new file mode 100644 index 0000000..6682d6d --- /dev/null +++ b/fs/afs/dir.c @@ -0,0 +1,666 @@ +/* dir.c: AFS filesystem directory handling + * + * Copyright (C) 2002 Red Hat, Inc. All Rights Reserved. + * Written by David Howells (dhowells@redhat.com) + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * as published by the Free Software Foundation; either version + * 2 of the License, or (at your option) any later version. + */ + +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/init.h> +#include <linux/sched.h> +#include <linux/slab.h> +#include <linux/fs.h> +#include <linux/pagemap.h> +#include <linux/smp_lock.h> +#include "vnode.h" +#include "volume.h" +#include <rxrpc/call.h> +#include "super.h" +#include "internal.h" + +static struct dentry *afs_dir_lookup(struct inode *dir, struct dentry *dentry, + struct nameidata *nd); +static int afs_dir_open(struct inode *inode, struct file *file); +static int afs_dir_readdir(struct file *file, void *dirent, filldir_t filldir); +static int afs_d_revalidate(struct dentry *dentry, struct nameidata *nd); +static int afs_d_delete(struct dentry *dentry); +static int afs_dir_lookup_filldir(void *_cookie, const char *name, int nlen, + loff_t fpos, ino_t ino, unsigned dtype); + +struct file_operations afs_dir_file_operations = { + .open = afs_dir_open, + .readdir = afs_dir_readdir, +}; + +struct inode_operations afs_dir_inode_operations = { + .lookup = afs_dir_lookup, + .getattr = afs_inode_getattr, +#if 0 /* TODO */ + .create = afs_dir_create, + .link = afs_dir_link, + .unlink = afs_dir_unlink, + .symlink = afs_dir_symlink, + .mkdir = afs_dir_mkdir, + .rmdir = afs_dir_rmdir, + .mknod = afs_dir_mknod, + .rename = afs_dir_rename, +#endif +}; + +static struct dentry_operations afs_fs_dentry_operations = { + .d_revalidate = afs_d_revalidate, + .d_delete = afs_d_delete, +}; + +#define AFS_DIR_HASHTBL_SIZE 128 +#define AFS_DIR_DIRENT_SIZE 32 +#define AFS_DIRENT_PER_BLOCK 64 + +union afs_dirent { + struct { + uint8_t valid; + uint8_t unused[1]; + __be16 hash_next; + __be32 vnode; + __be32 unique; + uint8_t name[16]; + uint8_t overflow[4]; /* if any char of the name (inc + * NUL) reaches here, consume + * the next dirent too */ + } u; + uint8_t extended_name[32]; +}; + +/* AFS directory page header (one at the beginning of every 2048-byte chunk) */ +struct afs_dir_pagehdr { + __be16 npages; + __be16 magic; +#define AFS_DIR_MAGIC htons(1234) + uint8_t nentries; + uint8_t bitmap[8]; + uint8_t pad[19]; +}; + +/* directory block layout */ +union afs_dir_block { + + struct afs_dir_pagehdr pagehdr; + + struct { + struct afs_dir_pagehdr pagehdr; + uint8_t alloc_ctrs[128]; + /* dir hash table */ + uint16_t hashtable[AFS_DIR_HASHTBL_SIZE]; + } hdr; + + union afs_dirent dirents[AFS_DIRENT_PER_BLOCK]; +}; + +/* layout on a linux VM page */ +struct afs_dir_page { + union afs_dir_block blocks[PAGE_SIZE / sizeof(union afs_dir_block)]; +}; + +struct afs_dir_lookup_cookie { + struct afs_fid fid; + const char *name; + size_t nlen; + int found; +}; + +/*****************************************************************************/ +/* + * check that a directory page is valid + */ +static inline void afs_dir_check_page(struct inode *dir, struct page *page) +{ + struct afs_dir_page *dbuf; + loff_t latter; + int tmp, qty; + +#if 0 + /* check the page count */ + qty = desc.size / sizeof(dbuf->blocks[0]); + if (qty == 0) + goto error; + + if (page->index==0 && qty!=ntohs(dbuf->blocks[0].pagehdr.npages)) { + printk("kAFS: %s(%lu): wrong number of dir blocks %d!=%hu\n", + __FUNCTION__,dir->i_ino,qty,ntohs(dbuf->blocks[0].pagehdr.npages)); + goto error; + } +#endif + + /* determine how many magic numbers there should be in this page */ + latter = dir->i_size - (page->index << PAGE_CACHE_SHIFT); + if (latter >= PAGE_SIZE) + qty = PAGE_SIZE; + else + qty = latter; + qty /= sizeof(union afs_dir_block); + + /* check them */ + dbuf = page_address(page); + for (tmp = 0; tmp < qty; tmp++) { + if (dbuf->blocks[tmp].pagehdr.magic != AFS_DIR_MAGIC) { + printk("kAFS: %s(%lu): bad magic %d/%d is %04hx\n", + __FUNCTION__, dir->i_ino, tmp, qty, + ntohs(dbuf->blocks[tmp].pagehdr.magic)); + goto error; + } + } + + SetPageChecked(page); + return; + + error: + SetPageChecked(page); + SetPageError(page); + +} /* end afs_dir_check_page() */ + +/*****************************************************************************/ +/* + * discard a page cached in the pagecache + */ +static inline void afs_dir_put_page(struct page *page) +{ + kunmap(page); + page_cache_release(page); + +} /* end afs_dir_put_page() */ + +/*****************************************************************************/ +/* + * get a page into the pagecache + */ +static struct page *afs_dir_get_page(struct inode *dir, unsigned long index) +{ + struct page *page; + + _enter("{%lu},%lu", dir->i_ino, index); + + page = read_cache_page(dir->i_mapping,index, + (filler_t *) dir->i_mapping->a_ops->readpage, + NULL); + if (!IS_ERR(page)) { + wait_on_page_locked(page); + kmap(page); + if (!PageUptodate(page)) + goto fail; + if (!PageChecked(page)) + afs_dir_check_page(dir, page); + if (PageError(page)) + goto fail; + } + return page; + + fail: + afs_dir_put_page(page); + return ERR_PTR(-EIO); +} /* end afs_dir_get_page() */ + +/*****************************************************************************/ +/* + * open an AFS directory file + */ +static int afs_dir_open(struct inode *inode, struct file *file) +{ + _enter("{%lu}", inode->i_ino); + + BUG_ON(sizeof(union afs_dir_block) != 2048); + BUG_ON(sizeof(union afs_dirent) != 32); + + if (AFS_FS_I(inode)->flags & AFS_VNODE_DELETED) + return -ENOENT; + + _leave(" = 0"); + return 0; + +} /* end afs_dir_open() */ + +/*****************************************************************************/ +/* + * deal with one block in an AFS directory + */ +static int afs_dir_iterate_block(unsigned *fpos, + union afs_dir_block *block, + unsigned blkoff, + void *cookie, + filldir_t filldir) +{ + union afs_dirent *dire; + unsigned offset, next, curr; + size_t nlen; + int tmp, ret; + + _enter("%u,%x,%p,,",*fpos,blkoff,block); + + curr = (*fpos - blkoff) / sizeof(union afs_dirent); + + /* walk through the block, an entry at a time */ + for (offset = AFS_DIRENT_PER_BLOCK - block->pagehdr.nentries; + offset < AFS_DIRENT_PER_BLOCK; + offset = next + ) { + next = offset + 1; + + /* skip entries marked unused in the bitmap */ + if (!(block->pagehdr.bitmap[offset / 8] & + (1 << (offset % 8)))) { + _debug("ENT[%Zu.%u]: unused\n", + blkoff / sizeof(union afs_dir_block), offset); + if (offset >= curr) + *fpos = blkoff + + next * sizeof(union afs_dirent); + continue; + } + + /* got a valid entry */ + dire = &block->dirents[offset]; + nlen = strnlen(dire->u.name, + sizeof(*block) - + offset * sizeof(union afs_dirent)); + + _debug("ENT[%Zu.%u]: %s %Zu \"%s\"\n", + blkoff / sizeof(union afs_dir_block), offset, + (offset < curr ? "skip" : "fill"), + nlen, dire->u.name); + + /* work out where the next possible entry is */ + for (tmp = nlen; tmp > 15; tmp -= sizeof(union afs_dirent)) { + if (next >= AFS_DIRENT_PER_BLOCK) { + _debug("ENT[%Zu.%u]:" + " %u travelled beyond end dir block" + " (len %u/%Zu)\n", + blkoff / sizeof(union afs_dir_block), + offset, next, tmp, nlen); + return -EIO; + } + if (!(block->pagehdr.bitmap[next / 8] & + (1 << (next % 8)))) { + _debug("ENT[%Zu.%u]:" + " %u unmarked extension (len %u/%Zu)\n", + blkoff / sizeof(union afs_dir_block), + offset, next, tmp, nlen); + return -EIO; + } + + _debug("ENT[%Zu.%u]: ext %u/%Zu\n", + blkoff / sizeof(union afs_dir_block), + next, tmp, nlen); + next++; + } + + /* skip if starts before the current position */ + if (offset < curr) + continue; + + /* found the next entry */ + ret = filldir(cookie, + dire->u.name, + nlen, + blkoff + offset * sizeof(union afs_dirent), + ntohl(dire->u.vnode), + filldir == afs_dir_lookup_filldir ? + ntohl(dire->u.unique) : DT_UNKNOWN); + if (ret < 0) { + _leave(" = 0 [full]"); + return 0; + } + + *fpos = blkoff + next * sizeof(union afs_dirent); + } + + _leave(" = 1 [more]"); + return 1; +} /* end afs_dir_iterate_block() */ + +/*****************************************************************************/ +/* + * read an AFS directory + */ +static int afs_dir_iterate(struct inode *dir, unsigned *fpos, void *cookie, + filldir_t filldir) +{ + union afs_dir_block *dblock; + struct afs_dir_page *dbuf; + struct page *page; + unsigned blkoff, limit; + int ret; + + _enter("{%lu},%u,,", dir->i_ino, *fpos); + + if (AFS_FS_I(dir)->flags & AFS_VNODE_DELETED) { + _leave(" = -ESTALE"); + return -ESTALE; + } + + /* round the file position up to the next entry boundary */ + *fpos += sizeof(union afs_dirent) - 1; + *fpos &= ~(sizeof(union afs_dirent) - 1); + + /* walk through the blocks in sequence */ + ret = 0; + while (*fpos < dir->i_size) { + blkoff = *fpos & ~(sizeof(union afs_dir_block) - 1); + + /* fetch the appropriate page from the directory */ + page = afs_dir_get_page(dir, blkoff / PAGE_SIZE); + if (IS_ERR(page)) { + ret = PTR_ERR(page); + break; + } + + limit = blkoff & ~(PAGE_SIZE - 1); + + dbuf = page_address(page); + + /* deal with the individual blocks stashed on this page */ + do { + dblock = &dbuf->blocks[(blkoff % PAGE_SIZE) / + sizeof(union afs_dir_block)]; + ret = afs_dir_iterate_block(fpos, dblock, blkoff, + cookie, filldir); + if (ret != 1) { + afs_dir_put_page(page); + goto out; + } + + blkoff += sizeof(union afs_dir_block); + + } while (*fpos < dir->i_size && blkoff < limit); + + afs_dir_put_page(page); + ret = 0; + } + + out: + _leave(" = %d", ret); + return ret; +} /* end afs_dir_iterate() */ + +/*****************************************************************************/ +/* + * read an AFS directory + */ +static int afs_dir_readdir(struct file *file, void *cookie, filldir_t filldir) +{ + unsigned fpos; + int ret; + + _enter("{%Ld,{%lu}}", file->f_pos, file->f_dentry->d_inode->i_ino); + + fpos = file->f_pos; + ret = afs_dir_iterate(file->f_dentry->d_inode, &fpos, cookie, filldir); + file->f_pos = fpos; + + _leave(" = %d", ret); + return ret; +} /* end afs_dir_readdir() */ + +/*****************************************************************************/ +/* + * search the directory for a name + * - if afs_dir_iterate_block() spots this function, it'll pass the FID + * uniquifier through dtype + */ +static int afs_dir_lookup_filldir(void *_cookie, const char *name, int nlen, + loff_t fpos, ino_t ino, unsigned dtype) +{ + struct afs_dir_lookup_cookie *cookie = _cookie; + + _enter("{%s,%Zu},%s,%u,,%lu,%u", + cookie->name, cookie->nlen, name, nlen, ino, dtype); + + if (cookie->nlen != nlen || memcmp(cookie->name, name, nlen) != 0) { + _leave(" = 0 [no]"); + return 0; + } + + cookie->fid.vnode = ino; + cookie->fid.unique = dtype; + cookie->found = 1; + + _leave(" = -1 [found]"); + return -1; +} /* end afs_dir_lookup_filldir() */ + +/*****************************************************************************/ +/* + * look up an entry in a directory + */ +static struct dentry *afs_dir_lookup(struct inode *dir, struct dentry *dentry, + struct nameidata *nd) +{ + struct afs_dir_lookup_cookie cookie; + struct afs_super_info *as; + struct afs_vnode *vnode; + struct inode *inode; + unsigned fpos; + int ret; + + _enter("{%lu},%p{%s}", dir->i_ino, dentry, dentry->d_name.name); + + /* insanity checks first */ + BUG_ON(sizeof(union afs_dir_block) != 2048); + BUG_ON(sizeof(union afs_dirent) != 32); + + if (dentry->d_name.len > 255) { + _leave(" = -ENAMETOOLONG"); + return ERR_PTR(-ENAMETOOLONG); + } + + vnode = AFS_FS_I(dir); + if (vnode->flags & AFS_VNODE_DELETED) { + _leave(" = -ESTALE"); + return ERR_PTR(-ESTALE); + } + + as = dir->i_sb->s_fs_info; + + /* search the directory */ + cookie.name = dentry->d_name.name; + cookie.nlen = dentry->d_name.len; + cookie.fid.vid = as->volume->vid; + cookie.found = 0; + + fpos = 0; + ret = afs_dir_iterate(dir, &fpos, &cookie, afs_dir_lookup_filldir); + if (ret < 0) { + _leave(" = %d", ret); + return ERR_PTR(ret); + } + + ret = -ENOENT; + if (!cookie.found) { + _leave(" = %d", ret); + return ERR_PTR(ret); + } + + /* instantiate the dentry */ + ret = afs_iget(dir->i_sb, &cookie.fid, &inode); + if (ret < 0) { + _leave(" = %d", ret); + return ERR_PTR(ret); + } + + dentry->d_op = &afs_fs_dentry_operations; + dentry->d_fsdata = (void *) (unsigned long) vnode->status.version; + + d_add(dentry, inode); + _leave(" = 0 { vn=%u u=%u } -> { ino=%lu v=%lu }", + cookie.fid.vnode, + cookie.fid.unique, + dentry->d_inode->i_ino, + dentry->d_inode->i_version); + + return NULL; +} /* end afs_dir_lookup() */ + +/*****************************************************************************/ +/* + * check that a dentry lookup hit has found a valid entry + * - NOTE! the hit can be a negative hit too, so we can't assume we have an + * inode + * (derived from nfs_lookup_revalidate) + */ +static int afs_d_revalidate(struct dentry *dentry, struct nameidata *nd) +{ + struct afs_dir_lookup_cookie cookie; + struct dentry *parent; + struct inode *inode, *dir; + unsigned fpos; + int ret; + + _enter("{sb=%p n=%s},", dentry->d_sb, dentry->d_name.name); + + /* lock down the parent dentry so we can peer at it */ + parent = dget_parent(dentry->d_parent); + + dir = parent->d_inode; + inode = dentry->d_inode; + + /* handle a negative dentry */ + if (!inode) + goto out_bad; + + /* handle a bad inode */ + if (is_bad_inode(inode)) { + printk("kAFS: afs_d_revalidate: %s/%s has bad inode\n", + dentry->d_parent->d_name.name, dentry->d_name.name); + goto out_bad; + } + + /* force a full look up if the parent directory changed since last the + * server was consulted + * - otherwise this inode must still exist, even if the inode details + * themselves have changed + */ + if (AFS_FS_I(dir)->flags & AFS_VNODE_CHANGED) + afs_vnode_fetch_status(AFS_FS_I(dir)); + + if (AFS_FS_I(dir)->flags & AFS_VNODE_DELETED) { + _debug("%s: parent dir deleted", dentry->d_name.name); + goto out_bad; + } + + if (AFS_FS_I(inode)->flags & AFS_VNODE_DELETED) { + _debug("%s: file already deleted", dentry->d_name.name); + goto out_bad; + } + + if ((unsigned long) dentry->d_fsdata != + (unsigned long) AFS_FS_I(dir)->status.version) { + _debug("%s: parent changed %lu -> %u", + dentry->d_name.name, + (unsigned long) dentry->d_fsdata, + (unsigned) AFS_FS_I(dir)->status.version); + + /* search the directory for this vnode */ + cookie.name = dentry->d_name.name; + cookie.nlen = dentry->d_name.len; + cookie.fid.vid = AFS_FS_I(inode)->volume->vid; + cookie.found = 0; + + fpos = 0; + ret = afs_dir_iterate(dir, &fpos, &cookie, + afs_dir_lookup_filldir); + if (ret < 0) { + _debug("failed to iterate dir %s: %d", + parent->d_name.name, ret); + goto out_bad; + } + + if (!cookie.found) { + _debug("%s: dirent not found", dentry->d_name.name); + goto not_found; + } + + /* if the vnode ID has changed, then the dirent points to a + * different file */ + if (cookie.fid.vnode != AFS_FS_I(inode)->fid.vnode) { + _debug("%s: dirent changed", dentry->d_name.name); + goto not_found; + } + + /* if the vnode ID uniqifier has changed, then the file has + * been deleted */ + if (cookie.fid.unique != AFS_FS_I(inode)->fid.unique) { + _debug("%s: file deleted (uq %u -> %u I:%lu)", + dentry->d_name.name, + cookie.fid.unique, + AFS_FS_I(inode)->fid.unique, + inode->i_version); + spin_lock(&AFS_FS_I(inode)->lock); + AFS_FS_I(inode)->flags |= AFS_VNODE_DELETED; + spin_unlock(&AFS_FS_I(inode)->lock); + invalidate_remote_inode(inode); + goto out_bad; + } + + dentry->d_fsdata = + (void *) (unsigned long) AFS_FS_I(dir)->status.version; + } + + out_valid: + dput(parent); + _leave(" = 1 [valid]"); + return 1; + + /* the dirent, if it exists, now points to a different vnode */ + not_found: + spin_lock(&dentry->d_lock); + dentry->d_flags |= DCACHE_NFSFS_RENAMED; + spin_unlock(&dentry->d_lock); + + out_bad: + if (inode) { + /* don't unhash if we have submounts */ + if (have_submounts(dentry)) + goto out_valid; + } + + shrink_dcache_parent(dentry); + + _debug("dropping dentry %s/%s", + dentry->d_parent->d_name.name, dentry->d_name.name); + d_drop(dentry); + + dput(parent); + + _leave(" = 0 [bad]"); + return 0; +} /* end afs_d_revalidate() */ + +/*****************************************************************************/ +/* + * allow the VFS to enquire as to whether a dentry should be unhashed (mustn't + * sleep) + * - called from dput() when d_count is going to 0. + * - return 1 to request dentry be unhashed, 0 otherwise + */ +static int afs_d_delete(struct dentry *dentry) +{ + _enter("%s", dentry->d_name.name); + + if (dentry->d_flags & DCACHE_NFSFS_RENAMED) + goto zap; + + if (dentry->d_inode) { + if (AFS_FS_I(dentry->d_inode)->flags & AFS_VNODE_DELETED) + goto zap; + } + + _leave(" = 0 [keep]"); + return 0; + + zap: + _leave(" = 1 [zap]"); + return 1; +} /* end afs_d_delete() */ |