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| -rw-r--r-- | fs/xfs/libxfs/xfs_attr.h | 621 |
1 files changed, 621 insertions, 0 deletions
diff --git a/fs/xfs/libxfs/xfs_attr.h b/fs/xfs/libxfs/xfs_attr.h new file mode 100644 index 000000000..81be9b3e4 --- /dev/null +++ b/fs/xfs/libxfs/xfs_attr.h @@ -0,0 +1,621 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * Copyright (c) 2000,2002-2003,2005 Silicon Graphics, Inc. + * All Rights Reserved. + */ +#ifndef __XFS_ATTR_H__ +#define __XFS_ATTR_H__ + +struct xfs_inode; +struct xfs_da_args; +struct xfs_attr_list_context; + +/* + * Large attribute lists are structured around Btrees where all the data + * elements are in the leaf nodes. Attribute names are hashed into an int, + * then that int is used as the index into the Btree. Since the hashval + * of an attribute name may not be unique, we may have duplicate keys. + * The internal links in the Btree are logical block offsets into the file. + * + * Small attribute lists use a different format and are packed as tightly + * as possible so as to fit into the literal area of the inode. + */ + +/* + * The maximum size (into the kernel or returned from the kernel) of an + * attribute value or the buffer used for an attr_list() call. Larger + * sizes will result in an ERANGE return code. + */ +#define ATTR_MAX_VALUELEN (64*1024) /* max length of a value */ + +/* + * Kernel-internal version of the attrlist cursor. + */ +struct xfs_attrlist_cursor_kern { + __u32 hashval; /* hash value of next entry to add */ + __u32 blkno; /* block containing entry (suggestion) */ + __u32 offset; /* offset in list of equal-hashvals */ + __u16 pad1; /* padding to match user-level */ + __u8 pad2; /* padding to match user-level */ + __u8 initted; /* T/F: cursor has been initialized */ +}; + + +/*======================================================================== + * Structure used to pass context around among the routines. + *========================================================================*/ + + +/* void; state communicated via *context */ +typedef void (*put_listent_func_t)(struct xfs_attr_list_context *, int, + unsigned char *, int, int); + +struct xfs_attr_list_context { + struct xfs_trans *tp; + struct xfs_inode *dp; /* inode */ + struct xfs_attrlist_cursor_kern cursor; /* position in list */ + void *buffer; /* output buffer */ + + /* + * Abort attribute list iteration if non-zero. Can be used to pass + * error values to the xfs_attr_list caller. + */ + int seen_enough; + bool allow_incomplete; + + ssize_t count; /* num used entries */ + int dupcnt; /* count dup hashvals seen */ + int bufsize; /* total buffer size */ + int firstu; /* first used byte in buffer */ + unsigned int attr_filter; /* XFS_ATTR_{ROOT,SECURE} */ + int resynch; /* T/F: resynch with cursor */ + put_listent_func_t put_listent; /* list output fmt function */ + int index; /* index into output buffer */ +}; + + +/* + * ======================================================================== + * Structure used to pass context around among the delayed routines. + * ======================================================================== + */ + +/* + * Below is a state machine diagram for attr remove operations. The XFS_DAS_* + * states indicate places where the function would return -EAGAIN, and then + * immediately resume from after being called by the calling function. States + * marked as a "subroutine state" indicate that they belong to a subroutine, and + * so the calling function needs to pass them back to that subroutine to allow + * it to finish where it left off. But they otherwise do not have a role in the + * calling function other than just passing through. + * + * xfs_attr_remove_iter() + * │ + * v + * have attr to remove? ──n──> done + * │ + * y + * │ + * v + * are we short form? ──y──> xfs_attr_shortform_remove ──> done + * │ + * n + * │ + * V + * are we leaf form? ──y──> xfs_attr_leaf_removename ──> done + * │ + * n + * │ + * V + * ┌── need to setup state? + * │ │ + * n y + * │ │ + * │ v + * │ find attr and get state + * │ attr has remote blks? ──n─┐ + * │ │ v + * │ │ find and invalidate + * │ y the remote blocks. + * │ │ mark attr incomplete + * │ ├────────────────┘ + * └──────────┤ + * │ + * v + * Have remote blks to remove? ───y─────┐ + * │ ^ remove the blks + * │ │ │ + * │ │ v + * │ XFS_DAS_RMTBLK <─n── done? + * │ re-enter with │ + * │ one less blk to y + * │ remove │ + * │ V + * │ refill the state + * n │ + * │ v + * │ XFS_DAS_RM_NAME + * │ │ + * ├─────────────────────────┘ + * │ + * v + * remove leaf and + * update hash with + * xfs_attr_node_remove_cleanup + * │ + * v + * need to + * shrink tree? ─n─┐ + * │ │ + * y │ + * │ │ + * v │ + * join leaf │ + * │ │ + * v │ + * XFS_DAS_RM_SHRINK │ + * │ │ + * v │ + * do the shrink │ + * │ │ + * v │ + * free state <──┘ + * │ + * v + * done + * + * + * Below is a state machine diagram for attr set operations. + * + * It seems the challenge with understanding this system comes from trying to + * absorb the state machine all at once, when really one should only be looking + * at it with in the context of a single function. Once a state sensitive + * function is called, the idea is that it "takes ownership" of the + * state machine. It isn't concerned with the states that may have belonged to + * it's calling parent. Only the states relevant to itself or any other + * subroutines there in. Once a calling function hands off the state machine to + * a subroutine, it needs to respect the simple rule that it doesn't "own" the + * state machine anymore, and it's the responsibility of that calling function + * to propagate the -EAGAIN back up the call stack. Upon reentry, it is + * committed to re-calling that subroutine until it returns something other than + * -EAGAIN. Once that subroutine signals completion (by returning anything other + * than -EAGAIN), the calling function can resume using the state machine. + * + * xfs_attr_set_iter() + * │ + * v + * ┌─y─ has an attr fork? + * │ | + * │ n + * │ | + * │ V + * │ add a fork + * │ │ + * └──────────┤ + * │ + * V + * ┌─── is shortform? + * │ │ + * │ y + * │ │ + * │ V + * │ xfs_attr_set_fmt + * │ | + * │ V + * │ xfs_attr_try_sf_addname + * │ │ + * │ V + * │ had enough ──y──> done + * │ space? + * n │ + * │ n + * │ │ + * │ V + * │ transform to leaf + * │ │ + * │ V + * │ hold the leaf buffer + * │ │ + * │ V + * │ return -EAGAIN + * │ Re-enter in + * │ leaf form + * │ + * └─> release leaf buffer + * if needed + * │ + * V + * ┌───n── fork has + * │ only 1 blk? + * │ │ + * │ y + * │ │ + * │ v + * │ xfs_attr_leaf_try_add() + * │ │ + * │ v + * │ had enough ──────────────y─────────────┐ + * │ space? │ + * │ │ │ + * │ n │ + * │ │ │ + * │ v │ + * │ return -EAGAIN │ + * │ re-enter in │ + * │ node form │ + * │ │ │ + * └──────────┤ │ + * │ │ + * V │ + * xfs_attr_node_addname_find_attr │ + * determines if this │ + * is create or rename │ + * find space to store attr │ + * │ │ + * v │ + * xfs_attr_node_addname │ + * │ │ + * v │ + * fits in a node leaf? ────n─────┐ │ + * │ ^ v │ + * │ │ single leaf node? │ + * │ │ │ │ │ + * y │ y n │ + * │ │ │ │ │ + * v │ v v │ + * update │ grow the leaf split if │ + * hashvals └── return -EAGAIN needed │ + * │ retry leaf add │ │ + * │ on reentry │ │ + * ├────────────────────────────┘ │ + * │ │ + * v │ + * need to alloc │ + * ┌─y── or flip flag? │ + * │ │ │ + * │ n │ + * │ │ │ + * │ v │ + * │ done │ + * │ │ + * │ │ + * │ XFS_DAS_FOUND_LBLK <────────────────┘ + * │ │ + * │ V + * │ xfs_attr_leaf_addname() + * │ │ + * │ v + * │ ┌──first time through? + * │ │ │ + * │ │ y + * │ │ │ + * │ n v + * │ │ if we have rmt blks + * │ │ find space for them + * │ │ │ + * │ └──────────┤ + * │ │ + * │ v + * │ still have + * │ ┌─n─ blks to alloc? <──┐ + * │ │ │ │ + * │ │ y │ + * │ │ │ │ + * │ │ v │ + * │ │ alloc one blk │ + * │ │ return -EAGAIN ──┘ + * │ │ re-enter with one + * │ │ less blk to alloc + * │ │ + * │ │ + * │ └───> set the rmt + * │ value + * │ │ + * │ v + * │ was this + * │ a rename? ──n─┐ + * │ │ │ + * │ y │ + * │ │ │ + * │ v │ + * │ flip incomplete │ + * │ flag │ + * │ │ │ + * │ v │ + * │ XFS_DAS_FLIP_LFLAG │ + * │ │ │ + * │ v │ + * │ need to remove │ + * │ old bks? ──n──┤ + * │ │ │ + * │ y │ + * │ │ │ + * │ V │ + * │ remove │ + * │ ┌───> old blks │ + * │ │ │ │ + * │ XFS_DAS_RM_LBLK │ │ + * │ ^ │ │ + * │ │ v │ + * │ └──y── more to │ + * │ remove? │ + * │ │ │ + * │ n │ + * │ │ │ + * │ v │ + * │ XFS_DAS_RD_LEAF │ + * │ │ │ + * │ v │ + * │ remove leaf │ + * │ │ │ + * │ v │ + * │ shrink to sf │ + * │ if needed │ + * │ │ │ + * │ v │ + * │ done <──────┘ + * │ + * └──────> XFS_DAS_FOUND_NBLK + * │ + * v + * ┌─────n── need to + * │ alloc blks? + * │ │ + * │ y + * │ │ + * │ v + * │ find space + * │ │ + * │ v + * │ ┌─>XFS_DAS_ALLOC_NODE + * │ │ │ + * │ │ v + * │ │ alloc blk + * │ │ │ + * │ │ v + * │ └──y── need to alloc + * │ more blocks? + * │ │ + * │ n + * │ │ + * │ v + * │ set the rmt value + * │ │ + * │ v + * │ was this + * └────────> a rename? ──n─┐ + * │ │ + * y │ + * │ │ + * v │ + * flip incomplete │ + * flag │ + * │ │ + * v │ + * XFS_DAS_FLIP_NFLAG │ + * │ │ + * v │ + * need to │ + * remove blks? ─n──┤ + * │ │ + * y │ + * │ │ + * v │ + * remove │ + * ┌────────> old blks │ + * │ │ │ + * XFS_DAS_RM_NBLK │ │ + * ^ │ │ + * │ v │ + * └──────y── more to │ + * remove │ + * │ │ + * n │ + * │ │ + * v │ + * XFS_DAS_CLR_FLAG │ + * │ │ + * v │ + * clear flags │ + * │ │ + * ├──────────┘ + * │ + * v + * done + */ + +/* + * Enum values for xfs_attr_intent.xattri_da_state + * + * These values are used by delayed attribute operations to keep track of where + * they were before they returned -EAGAIN. A return code of -EAGAIN signals the + * calling function to roll the transaction, and then call the subroutine to + * finish the operation. The enum is then used by the subroutine to jump back + * to where it was and resume executing where it left off. + */ +enum xfs_delattr_state { + XFS_DAS_UNINIT = 0, /* No state has been set yet */ + + /* + * Initial sequence states. The replace setup code relies on the + * ADD and REMOVE states for a specific format to be sequential so + * that we can transform the initial operation to be performed + * according to the xfs_has_larp() state easily. + */ + XFS_DAS_SF_ADD, /* Initial sf add state */ + XFS_DAS_SF_REMOVE, /* Initial sf replace/remove state */ + + XFS_DAS_LEAF_ADD, /* Initial leaf add state */ + XFS_DAS_LEAF_REMOVE, /* Initial leaf replace/remove state */ + + XFS_DAS_NODE_ADD, /* Initial node add state */ + XFS_DAS_NODE_REMOVE, /* Initial node replace/remove state */ + + /* Leaf state set/replace/remove sequence */ + XFS_DAS_LEAF_SET_RMT, /* set a remote xattr from a leaf */ + XFS_DAS_LEAF_ALLOC_RMT, /* We are allocating remote blocks */ + XFS_DAS_LEAF_REPLACE, /* Perform replace ops on a leaf */ + XFS_DAS_LEAF_REMOVE_OLD, /* Start removing old attr from leaf */ + XFS_DAS_LEAF_REMOVE_RMT, /* A rename is removing remote blocks */ + XFS_DAS_LEAF_REMOVE_ATTR, /* Remove the old attr from a leaf */ + + /* Node state sequence, must match leaf state above */ + XFS_DAS_NODE_SET_RMT, /* set a remote xattr from a node */ + XFS_DAS_NODE_ALLOC_RMT, /* We are allocating remote blocks */ + XFS_DAS_NODE_REPLACE, /* Perform replace ops on a node */ + XFS_DAS_NODE_REMOVE_OLD, /* Start removing old attr from node */ + XFS_DAS_NODE_REMOVE_RMT, /* A rename is removing remote blocks */ + XFS_DAS_NODE_REMOVE_ATTR, /* Remove the old attr from a node */ + + XFS_DAS_DONE, /* finished operation */ +}; + +#define XFS_DAS_STRINGS \ + { XFS_DAS_UNINIT, "XFS_DAS_UNINIT" }, \ + { XFS_DAS_SF_ADD, "XFS_DAS_SF_ADD" }, \ + { XFS_DAS_SF_REMOVE, "XFS_DAS_SF_REMOVE" }, \ + { XFS_DAS_LEAF_ADD, "XFS_DAS_LEAF_ADD" }, \ + { XFS_DAS_LEAF_REMOVE, "XFS_DAS_LEAF_REMOVE" }, \ + { XFS_DAS_NODE_ADD, "XFS_DAS_NODE_ADD" }, \ + { XFS_DAS_NODE_REMOVE, "XFS_DAS_NODE_REMOVE" }, \ + { XFS_DAS_LEAF_SET_RMT, "XFS_DAS_LEAF_SET_RMT" }, \ + { XFS_DAS_LEAF_ALLOC_RMT, "XFS_DAS_LEAF_ALLOC_RMT" }, \ + { XFS_DAS_LEAF_REPLACE, "XFS_DAS_LEAF_REPLACE" }, \ + { XFS_DAS_LEAF_REMOVE_OLD, "XFS_DAS_LEAF_REMOVE_OLD" }, \ + { XFS_DAS_LEAF_REMOVE_RMT, "XFS_DAS_LEAF_REMOVE_RMT" }, \ + { XFS_DAS_LEAF_REMOVE_ATTR, "XFS_DAS_LEAF_REMOVE_ATTR" }, \ + { XFS_DAS_NODE_SET_RMT, "XFS_DAS_NODE_SET_RMT" }, \ + { XFS_DAS_NODE_ALLOC_RMT, "XFS_DAS_NODE_ALLOC_RMT" }, \ + { XFS_DAS_NODE_REPLACE, "XFS_DAS_NODE_REPLACE" }, \ + { XFS_DAS_NODE_REMOVE_OLD, "XFS_DAS_NODE_REMOVE_OLD" }, \ + { XFS_DAS_NODE_REMOVE_RMT, "XFS_DAS_NODE_REMOVE_RMT" }, \ + { XFS_DAS_NODE_REMOVE_ATTR, "XFS_DAS_NODE_REMOVE_ATTR" }, \ + { XFS_DAS_DONE, "XFS_DAS_DONE" } + +struct xfs_attri_log_nameval; + +/* + * Context used for keeping track of delayed attribute operations + */ +struct xfs_attr_intent { + /* + * used to log this item to an intent containing a list of attrs to + * commit later + */ + struct list_head xattri_list; + + /* Used in xfs_attr_node_removename to roll through removing blocks */ + struct xfs_da_state *xattri_da_state; + + struct xfs_da_args *xattri_da_args; + + /* + * Shared buffer containing the attr name and value so that the logging + * code can share large memory buffers between log items. + */ + struct xfs_attri_log_nameval *xattri_nameval; + + /* Used to keep track of current state of delayed operation */ + enum xfs_delattr_state xattri_dela_state; + + /* + * Attr operation being performed - XFS_ATTRI_OP_FLAGS_* + */ + unsigned int xattri_op_flags; + + /* Used in xfs_attr_rmtval_set_blk to roll through allocating blocks */ + xfs_dablk_t xattri_lblkno; + int xattri_blkcnt; + struct xfs_bmbt_irec xattri_map; +}; + + +/*======================================================================== + * Function prototypes for the kernel. + *========================================================================*/ + +/* + * Overall external interface routines. + */ +int xfs_attr_inactive(struct xfs_inode *dp); +int xfs_attr_list_ilocked(struct xfs_attr_list_context *); +int xfs_attr_list(struct xfs_attr_list_context *); +int xfs_inode_hasattr(struct xfs_inode *ip); +bool xfs_attr_is_leaf(struct xfs_inode *ip); +int xfs_attr_get_ilocked(struct xfs_da_args *args); +int xfs_attr_get(struct xfs_da_args *args); +int xfs_attr_set(struct xfs_da_args *args); +int xfs_attr_set_iter(struct xfs_attr_intent *attr); +int xfs_attr_remove_iter(struct xfs_attr_intent *attr); +bool xfs_attr_namecheck(const void *name, size_t length); +int xfs_attr_calc_size(struct xfs_da_args *args, int *local); +void xfs_init_attr_trans(struct xfs_da_args *args, struct xfs_trans_res *tres, + unsigned int *total); + +/* + * Check to see if the attr should be upgraded from non-existent or shortform to + * single-leaf-block attribute list. + */ +static inline bool +xfs_attr_is_shortform( + struct xfs_inode *ip) +{ + return ip->i_af.if_format == XFS_DINODE_FMT_LOCAL || + (ip->i_af.if_format == XFS_DINODE_FMT_EXTENTS && + ip->i_af.if_nextents == 0); +} + +static inline enum xfs_delattr_state +xfs_attr_init_add_state(struct xfs_da_args *args) +{ + /* + * When called from the completion of a attr remove to determine the + * next state, the attribute fork may be null. This can occur only occur + * on a pure remove, but we grab the next state before we check if a + * replace operation is being performed. If we are called from any other + * context, i_af is guaranteed to exist. Hence if the attr fork is + * null, we were called from a pure remove operation and so we are done. + */ + if (!xfs_inode_has_attr_fork(args->dp)) + return XFS_DAS_DONE; + + args->op_flags |= XFS_DA_OP_ADDNAME; + if (xfs_attr_is_shortform(args->dp)) + return XFS_DAS_SF_ADD; + if (xfs_attr_is_leaf(args->dp)) + return XFS_DAS_LEAF_ADD; + return XFS_DAS_NODE_ADD; +} + +static inline enum xfs_delattr_state +xfs_attr_init_remove_state(struct xfs_da_args *args) +{ + args->op_flags |= XFS_DA_OP_REMOVE; + if (xfs_attr_is_shortform(args->dp)) + return XFS_DAS_SF_REMOVE; + if (xfs_attr_is_leaf(args->dp)) + return XFS_DAS_LEAF_REMOVE; + return XFS_DAS_NODE_REMOVE; +} + +/* + * If we are logging the attributes, then we have to start with removal of the + * old attribute so that there is always consistent state that we can recover + * from if the system goes down part way through. We always log the new attr + * value, so even when we remove the attr first we still have the information in + * the log to finish the replace operation atomically. + */ +static inline enum xfs_delattr_state +xfs_attr_init_replace_state(struct xfs_da_args *args) +{ + args->op_flags |= XFS_DA_OP_ADDNAME | XFS_DA_OP_REPLACE; + if (args->op_flags & XFS_DA_OP_LOGGED) + return xfs_attr_init_remove_state(args); + return xfs_attr_init_add_state(args); +} + +extern struct kmem_cache *xfs_attr_intent_cache; +int __init xfs_attr_intent_init_cache(void); +void xfs_attr_intent_destroy_cache(void); + +#endif /* __XFS_ATTR_H__ */ |